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| Software | Description |
|---|---|
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RHEL 6
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refers to RHEL 6 and higher
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GFS2
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refers to GFS2 for RHEL 6 and higher
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Logical_Volume_Manager_Administration(EN)-6 (2010-10-14T15:20).
Mono-spaced Bold
To see the contents of the filemy_next_bestselling_novelin your current working directory, enter thecat my_next_bestselling_novelcommand at the shell prompt and press Enter to execute the command.
Press Enter to execute the command.Press Ctrl+Alt+F2 to switch to the first virtual terminal. Press Ctrl+Alt+F1 to return to your X-Windows session.
mono-spaced bold. For example:
File-related classes includefilesystemfor file systems,filefor files, anddirfor directories. Each class has its own associated set of permissions.
Choose → → from the main menu bar to launch Mouse Preferences. In the Buttons tab, click the Left-handed mouse check box and click to switch the primary mouse button from the left to the right (making the mouse suitable for use in the left hand).To insert a special character into a gedit file, choose → → from the main menu bar. Next, choose → from the Character Map menu bar, type the name of the character in the Search field and click . The character you sought will be highlighted in the Character Table. Double-click this highlighted character to place it in the Text to copy field and then click the button. Now switch back to your document and choose → from the gedit menu bar.
Mono-spaced Bold Italic or Proportional Bold Italic
To connect to a remote machine using ssh, typesshat a shell prompt. If the remote machine isusername@domain.nameexample.comand your username on that machine is john, typessh john@example.com.Themount -o remountcommand remounts the named file system. For example, to remount thefile-system/homefile system, the command ismount -o remount /home.To see the version of a currently installed package, use therpm -qcommand. It will return a result as follows:package.package-version-release
Publican is a DocBook publishing system.
mono-spaced roman and presented thus:
books Desktop documentation drafts mss photos stuff svn books_tests Desktop1 downloads images notes scripts svgs
mono-spaced roman but add syntax highlighting as follows:
package org.jboss.book.jca.ex1; import javax.naming.InitialContext; public class ExClient { public static void main(String args[]) throws Exception { InitialContext iniCtx = new InitialContext(); Object ref = iniCtx.lookup("EchoBean"); EchoHome home = (EchoHome) ref; Echo echo = home.create(); System.out.println("Created Echo"); System.out.println("Echo.echo('Hello') = " + echo.echo("Hello")); } }
mirror_image_fault_policy and mirror_log_fault_policy parameters in the activation section of the lvm.conf file. When this parameter is set to remove, the system attempts to remove the faulty device and run without it. When this parameter is set to allocate,
the system attempts to remove the faulty device and tries to allocate
space on a new device to be a replacement for the failed device; this
policy acts like the remove policy if no
suitable device and space can be allocated for the replacement. For
information on the LVM mirror failure policies, see Section 4.4.3.1, “Mirrored Logical Volume Failure Policy”.
data_alignment_detection and data_alignment_offset_detection in the lvm.conf file, although disabling this support is not recommended.
data_alignment_detection and data_alignment_offset_detection, see the inline documentation for the /etc/lvm/lvm.conf file, which is also documented in Appendix B, The LVM Configuration Files. For general information on support for the I/O Stack and I/O limits in Red Hat Enterprise Linux 6, see the Storage Administration Guide.
udev integration. This synchronizes the Device Mapper with all udev processing related to Device Mapper devices, including LVM devices. For information on Device Mapper support for the udev device manager, see Section A.3, “Device Mapper Support for the udev Device Manager”.
lvconvert --repair command to repair a mirror after disk failure. This brings the mirror back into a consistent state. For information on the lvconvert --repair command, see Section 4.4.3.3, “Repairing a Mirrored Logical Device”.
--merge option of the lvconvert command to merge a snapshot into its origin volume. For information on merging snapshots, see Section 4.4.5, “Merging Snapshot Volumes”.
--splitmirrors argument of the lvconvert
command to split off a redundant image of a mirrored logical volume to
form a new logical volume. For information on using this option, see Section 4.4.3.2, “Splitting Off a Redundant Image of a Mirrored Logical Volume”.
--mirrorlog mirrored argument of the lvcreate command when creating a mirrored logical device. For information on using this option, see Section 4.4.3, “Creating Mirrored Volumes”.
vgconvert command. For information on converting LVM metadata format, see the vgconvert(8) man page.

clvmd daemon, must be running. The clvmd daemon is the key clustering extension to LVM. The clvmd
daemon runs in each cluster computer and distributes LVM metadata
updates in a cluster, presenting each cluster computer with the same
view of the logical volumes. For information on installing and
administering the High Availability Add-On see Configuring and Managing a Red Hat Cluster.
clvmd is started at boot time, you can execute a chkconfig ... on command on the clvmd service, as follows:
# chkconfig clvmd onclvmd daemon has not been started, you can execute a service ... start command on the clvmd service, as follows:
# service clvmd start
lvm.conf file for cluster-wide locking. Information on configuring the lvm.conf file to support clustered locking is provided within the lvm.conf file itself. For information about the lvm.conf file, see Appendix B, The LVM Configuration Files.


VG1 with a physical extent size of 4MB. This volume group includes 2 physical volumes named PV1 and PV2. The physical volumes are divided into 4MB units, since that is the extent size. In this example, PV1 is 100 extents in size (400MB) and PV2
is 200 extents in size (800MB). You can create a linear volume any size
between 1 and 300 extents (4MB to 1200MB). In this example, the linear
volume named LV1 is 300 extents in size.

LV1, which is 250 extents in size (1000MB) and LV2 which is 50 extents in size (200MB).



/usr, would need less space than a long-lived snapshot of a volume that sees a greater number of writes, such as /home.
fsck command on a
snapshot file system to check the file system integrity and determine
whether the original file system requires file system repair.
--merge option of the lvconvert
command to merge a snapshot into its origin volume. One use for this
feature is to perform system rollback if you have lost data or files or
otherwise need to restore your system to a previous state. After you
merge the snapshot volume, the resulting logical volume will have the
origin volume's name, minor number, and UUID and the merged snapshot is
removed. For information on using this option, see Section 4.4.5, “Merging Snapshot Volumes”.
clvmd daemon, must be started at boot time, as described in Section 1.4, “The Clustered Logical Volume Manager (CLVM)”.
lvm.conf file for cluster-wide locking. Information on configuring the lvm.conf file to support clustered locking is provided within the lvm.conf file itself. For information about the lvm.conf file, see Appendix B, The LVM Configuration Files.
mkfs.gfs2 command.
mkdir command. In a clustered system, create the mount point on all nodes in the cluster.
fstab file for each node in the system.
lvm.conf file. By default, the metadata backup is stored in the /etc/lvm/backup file and the metadata archives are stored in the /etc/lvm/archive file. How long the metadata archives stored in the /etc/lvm/archive file are kept and how many archive files are kept is determined by parameters you can set in the lvm.conf file. A daily system backup should include the contents of the /etc/lvm directory in the backup.
/etc/lvm/backup file with the vgcfgbackup command. You can restore metadata with the vgcfgrestore command. The vgcfgbackup and vgcfgrestore commands are described in Section 4.3.12, “Backing Up Volume Group Metadata”.
/etc/lvm/lvm.conf file, which is described in Appendix B, The LVM Configuration Files.
clvmd daemon. For information, see see Section 3.1, “Creating LVM Volumes in a Cluster”.
--units
argument in a command, lower-case indicates that units are in multiples
of 1024 while upper-case indicates that units are in multiples of 1000.
lvol0 in a volume group called vg0 can be specified as vg0/lvol0.
Where a list of volume groups is required but is left empty, a list of
all volume groups will be substituted. Where a list of logical volumes
is required but a volume group is given, a list of all the logical
volumes in that volume group will be substituted. For example, the lvdisplay vg0 command will display all the logical volumes in volume group vg0.
-v argument,
which can be entered multiple times to increase the output verbosity.
For example, the following examples shows the default output of the lvcreate command.
# lvcreate -L 50MB new_vg
Rounding up size to full physical extent 52.00 MB
Logical volume "lvol0" created
lvcreate command with the -v argument.
# lvcreate -v -L 50MB new_vg
Finding volume group "new_vg"
Rounding up size to full physical extent 52.00 MB
Archiving volume group "new_vg" metadata (seqno 4).
Creating logical volume lvol0
Creating volume group backup "/etc/lvm/backup/new_vg" (seqno 5).
Found volume group "new_vg"
Creating new_vg-lvol0
Loading new_vg-lvol0 table
Resuming new_vg-lvol0 (253:2)
Clearing start of logical volume "lvol0"
Creating volume group backup "/etc/lvm/backup/new_vg" (seqno 5).
Logical volume "lvol0" created
-vv, -vvv or the -vvvv argument to display increasingly more details about the command execution. The -vvvv
argument provides the maximum amount of information at this time. The
following example shows only the first few lines of output for the lvcreate command with the -vvvv argument specified.
# lvcreate -vvvv -L 50MB new_vg
#lvmcmdline.c:913 Processing: lvcreate -vvvv -L 50MB new_vg
#lvmcmdline.c:916 O_DIRECT will be used
#config/config.c:864 Setting global/locking_type to 1
#locking/locking.c:138 File-based locking selected.
#config/config.c:841 Setting global/locking_dir to /var/lock/lvm
#activate/activate.c:358 Getting target version for linear
#ioctl/libdm-iface.c:1569 dm version OF [16384]
#ioctl/libdm-iface.c:1569 dm versions OF [16384]
#activate/activate.c:358 Getting target version for striped
#ioctl/libdm-iface.c:1569 dm versions OF [16384]
#config/config.c:864 Setting activation/mirror_region_size to 512
...
--help argument of the command.
commandname --help
man command:
man commandnameman lvm command provides general online information about LVM.
/dev/sdf which is part of a volume group and, when you plug it back in, you find that it is now /dev/sdk.
LVM will still find the physical volume because it identifies the
physical volume by its UUID and not its device name. For information on
specifying the UUID of a physical volume when creating a physical
volume, see see Section 6.4, “Recovering Physical Volume Metadata”.
fdisk or cfdisk
command or an equivalent. For whole disk devices only the partition
table must be erased, which will effectively destroy all data on that
disk. You can remove an existing partition table by zeroing the first
sector with the following command:
dd if=/dev/zero of=PhysicalVolume bs=512 count=1
pvcreate command to initialize a block device to be used as a physical volume. Initialization is analogous to formatting a file system.
/dev/sdd1, /dev/sde1, and /dev/sdf1 for use as LVM physical volumes.
pvcreate /dev/sdd1 /dev/sde1 /dev/sdf1
pvcreate command on the partition. The following example initializes the partition /dev/hdb1 as an LVM physical volume for later use as part of an LVM logical volume.
pvcreate /dev/hdb1
lvmdiskscan command, as shown in the following example.
# lvmdiskscan
/dev/ram0 [ 16.00 MB]
/dev/sda [ 17.15 GB]
/dev/root [ 13.69 GB]
/dev/ram [ 16.00 MB]
/dev/sda1 [ 17.14 GB] LVM physical volume
/dev/VolGroup00/LogVol01 [ 512.00 MB]
/dev/ram2 [ 16.00 MB]
/dev/new_vg/lvol0 [ 52.00 MB]
/dev/ram3 [ 16.00 MB]
/dev/pkl_new_vg/sparkie_lv [ 7.14 GB]
/dev/ram4 [ 16.00 MB]
/dev/ram5 [ 16.00 MB]
/dev/ram6 [ 16.00 MB]
/dev/ram7 [ 16.00 MB]
/dev/ram8 [ 16.00 MB]
/dev/ram9 [ 16.00 MB]
/dev/ram10 [ 16.00 MB]
/dev/ram11 [ 16.00 MB]
/dev/ram12 [ 16.00 MB]
/dev/ram13 [ 16.00 MB]
/dev/ram14 [ 16.00 MB]
/dev/ram15 [ 16.00 MB]
/dev/sdb [ 17.15 GB]
/dev/sdb1 [ 17.14 GB] LVM physical volume
/dev/sdc [ 17.15 GB]
/dev/sdc1 [ 17.14 GB] LVM physical volume
/dev/sdd [ 17.15 GB]
/dev/sdd1 [ 17.14 GB] LVM physical volume
7 disks
17 partitions
0 LVM physical volume whole disks
4 LVM physical volumes
pvs, pvdisplay, and pvscan.
pvs command provides physical volume information in a configurable form, displaying one line per physical volume. The pvs command provides a great deal of format control, and is useful for scripting. For information on using the pvs command to customize your output, see Section 4.8, “Customized Reporting for LVM”.
pvdisplay command provides a
verbose multi-line output for each physical volume. It displays physical
properties (size, extents, volume group, etc.) in a fixed format.
pvdisplay command for a single physical volume.
# pvdisplay
--- Physical volume ---
PV Name /dev/sdc1
VG Name new_vg
PV Size 17.14 GB / not usable 3.40 MB
Allocatable yes
PE Size (KByte) 4096
Total PE 4388
Free PE 4375
Allocated PE 13
PV UUID Joqlch-yWSj-kuEn-IdwM-01S9-XO8M-mcpsVe
pvscan command scans all supported LVM block devices in the system for physical volumes.
# pvscan
PV /dev/sdb2 VG vg0 lvm2 [964.00 MB / 0 free]
PV /dev/sdc1 VG vg0 lvm2 [964.00 MB / 428.00 MB free]
PV /dev/sdc2 lvm2 [964.84 MB]
Total: 3 [2.83 GB] / in use: 2 [1.88 GB] / in no VG: 1 [964.84 MB]
lvm.conf
so that this command will avoid scanning specific physical volumes. For
information on using filters to control which devices are scanned, see Section 4.5, “Controlling LVM Device Scans with Filters”.
pvchange command. This may be necessary if there are disk errors, or if you will be removing the physical volume.
/dev/sdk1.
pvchange -x n /dev/sdk1
-xy arguments of the pvchange command to allow allocation where it had previously been disallowed.
pvresize command to update LVM with the new size. You can execute this command while LVM is using the physical volume.
pvremove command. Executing the pvremove command zeroes the LVM metadata on an empty physical volume.
vgreduce command, as described in Section 4.3.6, “Removing Physical Volumes from a Volume Group”.
# pvremove /dev/ram15
Labels on physical volume "/dev/ram15" successfully wiped
vgcreate command. The vgcreate command creates a new volume group by name and adds at least one physical volume to it.
vg1 that contains physical volumes /dev/sdd1 and /dev/sde1.
vgcreate vg1 /dev/sdd1 /dev/sde1
-s option to the vgcreate
command if the default extent size is not suitable. You can put limits
on the number of physical or logical volumes the volume group can have
by using the -p and -l arguments of the vgcreate command.
normal allocation policy. You can use the --alloc argument of the vgcreate command to specify an allocation policy of contiguous, anywhere, or cling.
contiguous policy requires that new
extents are adjacent to existing extents. If there are sufficient free
extents to satisfy an allocation request but a normal allocation policy would not use them, the anywhere allocation policy will, even if that reduces performance by placing two stripes on the same physical volume. The cling
policy places new extents on the same physical volume as existing
extents in the same stripe of the logical volume. These policies can be
changed using the vgchange command.
normal are required only in special cases where you need to specify unusual or nonstandard extent allocation.
/dev directory with the following layout:
/dev/vg/lv/
myvg1 and myvg2, each with three logical volumes named lvo1, lvo2, and lvo3, this create six device special files:
/dev/myvg1/lv01 /dev/myvg1/lv02 /dev/myvg1/lv03 /dev/myvg2/lv01 /dev/myvg2/lv02 /dev/myvg2/lv03
vgcreate command, just as you create them on a single node.
-c n of the vgcreate command.
vg1 that contains physical volumes /dev/sdd1 and /dev/sde1.
vgcreate -c n vg1 /dev/sdd1 /dev/sde1
-c option of the vgchange command, which is described in Section 4.3.7, “Changing the Parameters of a Volume Group”.
vgs command, which displays the c attribute if the volume is clustered. The following command displays the attributes of the volume groups VolGroup00 and testvg1. In this example, VolGroup00 is not clustered, while testvg1 is clustered, as indicated by the c attribute under the Attr heading.
[root@doc-07]# vgs
VG #PV #LV #SN Attr VSize VFree
VolGroup00 1 2 0 wz--n- 19.88G 0
testvg1 1 1 0 wz--nc 46.00G 8.00M
vgs command, see Section 4.3.4, “Displaying Volume Groups”Section 4.8, “Customized Reporting for LVM”, and the vgs man page.
vgextend command. The vgextend command increases a volume group's capacity by adding one or more free physical volumes.
/dev/sdf1 to the volume group vg1.
vgextend vg1 /dev/sdf1
vgs and vgdisplay.
vgscan command, which scans all the
disks for volume groups and rebuilds the LVM cache file, also displays
the volume groups. For information on the vgscan command, see Section 4.3.5, “Scanning Disks for Volume Groups to Build the Cache File”.
vgs command provides volume group information in a configurable form, displaying one line per volume group. The vgs command provides a great deal of format control, and is useful for scripting. For information on using the vgs command to customize your output, see Section 4.8, “Customized Reporting for LVM”.
vgdisplay command displays volume
group properties (such as size, extents, number of physical volumes,
etc.) in a fixed form. The following example shows the output of a vgdisplay command for the volume group new_vg. If you do not specify a volume group, all existing volume groups are displayed.
# vgdisplay new_vg
--- Volume group ---
VG Name new_vg
System ID
Format lvm2
Metadata Areas 3
Metadata Sequence No 11
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 1
Open LV 0
Max PV 0
Cur PV 3
Act PV 3
VG Size 51.42 GB
PE Size 4.00 MB
Total PE 13164
Alloc PE / Size 13 / 52.00 MB
Free PE / Size 13151 / 51.37 GB
VG UUID jxQJ0a-ZKk0-OpMO-0118-nlwO-wwqd-fD5D32
vgscan command scans all supported
disk devices in the system looking for LVM physical volumes and volume
groups. This builds the LVM cache in the /etc/lvm/.cache file, which maintains a listing of current LVM devices.
vgscan command automatically at system startup and at other times during LVM operation, such as when you execute a vgcreate command or when LVM detects an inconsistency.
vgscan command
manually when you change your hardware configuration and add or delete a
device from a node, causing new devices to be visible to the system
that were not present at system bootup. This may be necessary, for
example, when you add new disks to the system on a SAN or hotplug a new
disk that has been labeled as a physical volume.
lvm.conf
file to restrict the scan to avoid specific devices. For information on
using filters to control which devices are scanned, see Section 4.5, “Controlling LVM Device Scans with Filters”.
vgscan command.
# vgscan
Reading all physical volumes. This may take a while...
Found volume group "new_vg" using metadata type lvm2
Found volume group "officevg" using metadata type lvm2
vgreduce command. The vgreduce
command shrinks a volume group's capacity by removing one or more empty
physical volumes. This frees those physical volumes to be used in
different volume groups or to be removed from the system.
pvdisplay command.
# pvdisplay /dev/hda1
-- Physical volume ---
PV Name /dev/hda1
VG Name myvg
PV Size 1.95 GB / NOT usable 4 MB [LVM: 122 KB]
PV# 1
PV Status available
Allocatable yes (but full)
Cur LV 1
PE Size (KByte) 4096
Total PE 499
Free PE 0
Allocated PE 499
PV UUID Sd44tK-9IRw-SrMC-MOkn-76iP-iftz-OVSen7
pvmove command. Then use the vgreduce command to remove the physical volume:
/dev/hda1 from the volume group my_volume_group.
# vgreduce my_volume_group /dev/hda1vgchange command is used to deactivate and activate volume groups, as described in Section 4.3.8, “Activating and Deactivating Volume Groups”. You can also use this command to change several volume group parameters for an existing volume group.
vg00 to 128.
vgchange -l 128 /dev/vg00
vgchange command, see the vgchange(8) man page.
-a (--available) argument of the vgchange command.
my_volume_group.
vgchange -a n my_volume_group
lvchange command, as described in Section 4.4.8, “Changing the Parameters of a Logical Volume Group”, For information on activating logical volumes on individual nodes in a cluster, see Section 4.7, “Activating Logical Volumes on Individual Nodes in a Cluster”.
vgremove command.
# vgremove officevg
Volume group "officevg" successfully removed
vgsplit command.
pvmove command to force the split.
smallvg from the original volume group bigvg.
# vgsplit bigvg smallvg /dev/ram15
Volume group "smallvg" successfully split from "bigvg"
vgmerge
command. You can merge an inactive "source" volume with an active or an
inactive "destination" volume if the physical extent sizes of the
volume are equal and the physical and logical volume summaries of both
volume groups fit into the destination volume groups limits.
my_vg into the active or inactive volume group databases giving verbose runtime information.
vgmerge -v databases my_vg
lvm.conf file. By default, the metadata backup is stored in the /etc/lvm/backup file and the metadata archives are stored in the /etc/lvm/archives file. You can manually back up the metadata to the /etc/lvm/backup file with the vgcfgbackup command.
vgcfrestore command restores the metadata of a volume group from the archive to all the physical volumes in the volume groups.
vgcfgrestore command to recover physical volume metadata, see Section 6.4, “Recovering Physical Volume Metadata”.
vgrename command to rename an existing volume group.
vg02 to my_volume_group
vgrename /dev/vg02 /dev/my_volume_group
vgrename vg02 my_volume_group
vgexport and vgimport commands when you do this.
vgexport command makes an inactive volume group inaccessible to the system, which allows you to detach its physical volumes. The vgimport command makes a volume group accessible to a machine again after the vgexport command has made it inactive.
-a n argument of the vgchange command to mark the volume group as inactive, which prevents any further activity on the volume group.
vgexport command to export the volume group. This prevents it from being accessed by the system from which you are removing it.
pvscan command, as in the following example.
[root@tng3-1]# pvscan
PV /dev/sda1 is in exported VG myvg [17.15 GB / 7.15 GB free]
PV /dev/sdc1 is in exported VG myvg [17.15 GB / 15.15 GB free]
PV /dev/sdd1 is in exported VG myvg [17.15 GB / 15.15 GB free]
...
vgimport command to import the volume group, making it accessible to the new system.
-a y argument of the vgchange command.
vgmknodes command. This command checks the LVM2 special files in the /dev directory that are needed for active logical volumes. It creates any special files that are missing removes unused ones.
vgmknodes command into the vgscan command by specifying the mknodes argument to the vgscan command.
lvcreate command. If you do not specify a name for the logical volume, the default name lvol# is used where # is the internal number of the logical volume.
vg1.
lvcreate -L 10G vg1
testlv in the volume group testvg, creating the block device /dev/testvg/testlv.
lvcreate -L1500 -n testlv testvg
gfslv from the free extents in volume group vg0.
lvcreate -L 50G -n gfslv vg0
-l argument of the lvcreate
command to specify the size of the logical volume in extents. You can
also use this argument to specify the percentage of the volume group to
use for the logical volume. The following command creates a logical
volume called mylv that uses 60% of the total space in volume group testvol.
lvcreate -l 60%VG -n mylv testvg
-l argument of the lvcreate
command to specify the percentage of the remaining free space in a
volume group as the size of the logical volume. The following command
creates a logical volume called yourlv that uses all of the unallocated space in the volume group testvol.
lvcreate -l 100%FREE -n yourlv testvg
-l argument of the lvcreate
command to create a logical volume that uses the entire volume group.
Another way to create a logical volume that uses the entire volume group
is to use the vgdisplay command to find the "Total PE" size and to use those results as input to the lvcreate command.
mylv that fills the volume group named testvg.
#vgdisplay testvg | grep "Total PE"Total PE 10230 #lvcreate -l 10230 testvg -n mylv
lvcreate command line. The following command creates a logical volume named testlv in volume group testvg allocated from the physical volume /dev/sdg1,
lvcreate -L 1500 -ntestlv testvg /dev/sdg1
/dev/sda1 and extents 50 through 125 of physical volume /dev/sdb1 in volume group testvg.
lvcreate -l 100 -n testlv testvg /dev/sda1:0-25 /dev/sdb1:50-125
/dev/sda1 and then continues laying out the logical volume at extent 100.
lvcreate -l 100 -n testlv testvg /dev/sda1:0-25:100-
inherit, which applies the same policy as for the volume group. These policies can be changed using the lvchange command. For information on allocation policies, see Section 4.3.1, “Creating Volume Groups”.
-i argument of the lvcreate
command. This determines over how many physical volumes the logical
volume will be striped. The number of stripes cannot be greater than the
number of physical volumes in the volume group (unless the --alloc anywhere argument is used).
gfslv, and is carved out of volume group vg0.
lvcreate -L 50G -i2 -I64 -n gfslv vg0
stripelv and is in volume group testvg. The stripe will use sectors 0-50 of /dev/sda1 and sectors 50-100 of /dev/sdb1.
# lvcreate -l 100 -i2 -nstripelv testvg /dev/sda1:0-50 /dev/sdb1:50-100
Using default stripesize 64.00 KB
Logical volume "stripelv" created
lvm.conf file must be set correctly to enable cluster locking. For an example of creating a mirrored volume in a cluster, see Section 5.5, “Creating a Mirrored LVM Logical Volume in a Cluster”.
-m argument of the lvcreate command. Specifying -m1 creates one mirror, which yields two copies of the file system: a linear logical volume plus one copy. Similarly, specifying -m2 creates two mirrors, yielding three copies of the file system.
mirrorlv, and is carved out of volume group vg0:
lvcreate -L 50G -m1 -n mirrorlv vg0
-R argument of the lvcreate command to specify the region size in MB. You can also change the default region size by editing the mirror_region_size setting in the lvm.conf file.
-R argument to the lvcreate command. For example, if your mirror size is 1.5TB, you could specify -R 2. If your mirror size is 3TB, you could specify -R 4. For a mirror size of 5TB, you could specify -R 8.
lvcreate -m1 -L 2T -R 2 -n mirror vol_group
--mirrorlog core argument; this
eliminates the need for an extra log device, but it requires that the
entire mirror be resynchronized at every reboot.
bigvg. The logical volume is named ondiskmirvol and has a single mirror. The volume is 12MB in size and keeps the mirror log in memory.
# lvcreate -L 12MB -m1 --mirrorlog core -n ondiskmirvol bigvg
Logical volume "ondiskmirvol" created
--alloc anywhere argument of the vgcreate command. This may degrade performance, but it allows you to create a mirror even if you have only two underlying devices.
vg0 consists of only two devices. This command creates a 500 megabyte volume named mirrorlv in the vg0 volume group.
lvcreate -L 500M -m1 -n mirrorlv -alloc anywhere vg0
--mirrorlog mirrored argument. The following command creates a mirrored logical volume from the volume group bigvg. The logical volume is named twologvol and has a single mirror. The volume is 12MB in size and the mirror log is mirrored, with each log kept on a separate device.
# lvcreate -L 12MB -m1 --mirrorlog mirrored -n twologvol bigvg
Logical volume "twologvol" created
--alloc anywhere argument of the vgcreate
command. This may degrade performance, but it allows you to create a
redundant mirror log even if you do not have sufficient underlying
devices for each log to be kept on a separate device than the mirror
legs.
nosync argument to indicate that an initial synchronization from the first device is not required.
mirrorlv, and it is carved out of volume group vg0. The first leg of the mirror is on device /dev/sda1, the second leg of the mirror is on device /dev/sdb1, and the mirror log is on /dev/sdc1.
lvcreate -L 500M -m1 -n mirrorlv vg0 /dev/sda1 /dev/sdb1 /dev/sdc1
mirrorlv, and it is carved out of volume group vg0. The first leg of the mirror is on extents 0 through 499 of device /dev/sda1, the second leg of the mirror is on extents 0 through 499 of device /dev/sdb1, and the mirror log starts on extent 0 of device /dev/sdc1. These are 1MB extents. If any of the specified extents have already been allocated, they will be ignored.
lvcreate -L 500M -m1 -n mirrorlv vg0 /dev/sda1:0-499 /dev/sdb1:0-499 /dev/sdc1:0
mirror_image_fault_policy and mirror_log_fault_policy parameters in the activation section of the lvm.conf file. When these parameters are set to remove, the system attempts to remove the faulty device and run without it. When this parameter is set to allocate,
the system attempts to remove the faulty device and tries to allocate
space on a new device to be a replacement for the failed device; this
policy acts like the remove policy if no suitable device and space can be allocated for the replacement.
mirror_log_fault_policy parameter is set to allocate.
Using this policy for the log is fast and maintains the ability to
remember the sync state through crashes and reboots. If you set this
policy to remove, when a log device fails
the mirror converts to using an in-memory log and the mirror will not
remember its sync status across crashes and reboots and the entire
mirror will be re-synced.
mirror_image_fault_policy parameter is set to remove.
With this policy, if a mirror image fails the mirror will convert to a
non-mirrored device if there is only one remaining good copy. Set this
policy to allocate for a mirror device is
slow, as it requires the mirror to resynchronize the devices, but it
will preserve the mirror characteristic of the device.
--splitmirrors argument of the lvconvert command, specifying the number of of redundant images to split off. You must use the --name argument of the command to specify a name for the newly-split-off logical volume.
copy from the mirrored logical volume vg/lv. The new logical volume contains two mirror legs. In this example, LVM selects which devices to split off.
lvconvert --splitmirrors 2 --name copy vg/lv
copy from the mirrored logical volume vg/lv. The new logical volume contains two mirror legs consisting of devices /dev/sdc1 and /dev/sde1.
lvconvert --splitmirrors 2 --name copy vg/lv /dev/sd[ce]1
lvconvert --repair command to repair a mirror after a disk failure. This brings the mirror back into a consistent state. The lvconvert --repair
command is an interactive command that prompts you to indicate whether
you want the system to attempt to replace any failed devices.
-y option on the command line.
-f option on the command line.
--use-policies argument to use the device replacement policies specified by the mirror_log_fault_policy and mirror_device_fault_policy parameters in the lvm.conf file.
lvconvert command. You can also use this command to reconfigure other mirror parameters of an existing logical volume, such as corelog.
lvconvert command to restore the mirror. This procedure is provided in Section 6.3, “Recovering from LVM Mirror Failure”.
vg00/lvol1 to a mirrored logical volume.
lvconvert -m1 vg00/lvol1
vg00/lvol1 to a linear logical volume, removing the mirror leg.
lvconvert -m0 vg00/lvol1
-s argument of the lvcreate command to create a snapshot volume. A snapshot volume is writeable.
/dev/vg00/snap. This creates a snapshot of the origin logical volume named /dev/vg00/lvol1.
If the original logical volume contains a file system, you can mount
the snapshot logical volume on an arbitrary directory in order to access
the contents of the file system to run a backup while the original file
system continues to get updated.
lvcreate --size 100M --snapshot --name snap /dev/vg00/lvol1
lvdisplay command yields output that includes a a list of all snapshot logical volumes and their status (active or inactive).
/dev/new_vg/lvol0, for which a snapshot volume /dev/new_vg/newvgsnap has been created.
# lvdisplay /dev/new_vg/lvol0
--- Logical volume ---
LV Name /dev/new_vg/lvol0
VG Name new_vg
LV UUID LBy1Tz-sr23-OjsI-LT03-nHLC-y8XW-EhCl78
LV Write Access read/write
LV snapshot status source of
/dev/new_vg/newvgsnap1 [active]
LV Status available
# open 0
LV Size 52.00 MB
Current LE 13
Segments 1
Allocation inherit
Read ahead sectors 0
Block device 253:2
lvs command, by default, displays
the origin volume and the current percentage of the snapshot volume
being used for each snapshot volume. The following example shows the
default output for the lvs command for a system that includes the logical volume /dev/new_vg/lvol0, for which a snapshot volume /dev/new_vg/newvgsnap has been created.
# lvs
LV VG Attr LSize Origin Snap% Move Log Copy%
lvol0 new_vg owi-a- 52.00M
newvgsnap1 new_vg swi-a- 8.00M lvol0 0.20
lvs command to be
sure it does not fill. A snapshot that is 100% full is lost completely,
as a write to unchanged parts of the origin would be unable to succeed
without corrupting the snapshot.
--merge option of the lvconvert
command to merge a snapshot into its origin volume. If both the origin
and snapshot volume are not open, the merge will start immediately.
Otherwise, the merge will start the first time either the origin or
snapshot are activated and both are closed. Merging a snapshot into an
origin that cannot be closed, for example a root filesystem, is deferred
until the next time the origin volume is activated. When merging
starts, the resulting logical volume will have the origin’s name, minor
number and UUID. While the merge is in progress, reads or writes to the
origin appear as they were directed to the snapshot being merged. When
the merge finishes, the merged snapshot is removed.
vg00/lvol1_snap into its origin.
lvconvert --merge vg00/lvol1_snap"
vg00/lvol1, vg00/lvol2, and vg00/lvol3 are all tagged with the tag @some_tag". The following command merges the snapshop logical volumes for all three volumes serially: vg00/lvol1, then vg00/lvol2, then vg00/lvol3. If the --background option were used, all snapshot logical volume merges would start in parallel.
lvconvert --merge @some_tag"
lvconvert --merge command, see the lvconvert(8) man page.
lvcreate and the lvchange commands by using the following arguments:
--persistent y --majormajor--minorminor
fsid parameter in the exports file may avoid the need to set a persistent device number within LVM.
lvreduce
command. If the logical volume contains a file system, be sure to
reduce the file system first (or use the LVM GUI) so that the logical
volume is always at least as large as the file system expects it to be.
lvol1 in volume group vg00 by 3 logical extents.
lvreduce -l -3 vg00/lvol1
lvchange command. For a listing of the parameters you can change, see the lvchange(8) man page.
lvchange command to
activate and deactivate logical volumes. To activate and deactivate all
the logical volumes in a volume group at the same time, use the vgchange command, as described in Section 4.3.7, “Changing the Parameters of a Volume Group”.
lvol1 in volume group vg00 to be read-only.
lvchange -pr vg00/lvol1
lvrename command.
lvold in volume group vg02 to lvnew.
lvrename /dev/vg02/lvold /dev/vg02/lvnew
lvrename vg02 lvold lvnew
lvremove
command. If the logical volume is currently mounted, unmount the volume
before removing it. In addition, in a clustered environment you must
deactivate a logical volume before it can be removed.
/dev/testvg/testlv from the volume group testvg. Note that in this case the logical volume has not been deactivated.
[root@tng3-1 lvm]#lvremove /dev/testvg/testlvDo you really want to remove active logical volume "testlv"? [y/n]:yLogical volume "testlv" successfully removed
lvchange -an command, in which case you would not see the prompt verifying whether you want to remove an active logical volume.
lvs, lvdisplay, and lvscan.
lvs command provides logical volume information in a configurable form, displaying one line per logical volume. The lvs command provides a great deal of format control, and is useful for scripting. For information on using the lvs command to customize your output, see Section 4.8, “Customized Reporting for LVM”.
lvdisplay command displays logical volume properties (such as size, layout, and mapping) in a fixed format.
lvol2 in vg00.
If snapshot logical volumes have been created for this original logical
volume, this command shows a list of all snapshot logical volumes and
their status (active or inactive) as well.
lvdisplay -v /dev/vg00/lvol2
lvscan command scans for all logical volumes in the system and lists them, as in the following example.
# lvscan
ACTIVE '/dev/vg0/gfslv' [1.46 GB] inherit
lvextend command.
/dev/myvg/homevol to 12 gigabytes.
# lvextend -L12G /dev/myvg/homevol
lvextend -- extending logical volume "/dev/myvg/homevol" to 12 GB
lvextend -- doing automatic backup of volume group "myvg"
lvextend -- logical volume "/dev/myvg/homevol" successfully extended
/dev/myvg/homevol.
# lvextend -L+1G /dev/myvg/homevol
lvextend -- extending logical volume "/dev/myvg/homevol" to 13 GB
lvextend -- doing automatic backup of volume group "myvg"
lvextend -- logical volume "/dev/myvg/homevol" successfully extended
lvcreate command, you can use the -l argument of the lvextend
command to specify the number of extents by which to increase the size
of the logical volume. You can also use this argument to specify a
percentage of the volume group, or a percentage of the remaining free
space in the volume group. The following command extends the logical
volume called testlv to fill all of the unallocated space in the volume group myvg.
[root@tng3-1 ~]# lvextend -l +100%FREE /dev/myvg/testlv
Extending logical volume testlv to 68.59 GB
Logical volume testlv successfully resized
vg that consists of two underlying physical volumes, as displayed with the following vgs command.
# vgs
VG #PV #LV #SN Attr VSize VFree
vg 2 0 0 wz--n- 271.31G 271.31G
#lvcreate -n stripe1 -L 271.31G -i 2 vgUsing default stripesize 64.00 KB Rounding up size to full physical extent 271.31 GB Logical volume "stripe1" created #lvs -a -o +devicesLV VG Attr LSize Origin Snap% Move Log Copy% Devices stripe1 vg -wi-a- 271.31G /dev/sda1(0),/dev/sdb1(0)
# vgs
VG #PV #LV #SN Attr VSize VFree
vg 2 1 0 wz--n- 271.31G 0
# vgextend vg /dev/sdc1 Volume group "vg" successfully extended # vgs VG #PV #LV #SN Attr VSize VFree vg 3 1 0 wz--n- 406.97G 135.66G
# lvextend vg/stripe1 -L 406G
Using stripesize of last segment 64.00 KB
Extending logical volume stripe1 to 406.00 GB
Insufficient suitable allocatable extents for logical volume stripe1: 34480
more required
#vgextend vg /dev/sdd1Volume group "vg" successfully extended #vgsVG #PV #LV #SN Attr VSize VFree vg 4 1 0 wz--n- 542.62G 271.31G #lvextend vg/stripe1 -L 542GUsing stripesize of last segment 64.00 KB Extending logical volume stripe1 to 542.00 GB Logical volume stripe1 successfully resized
lvextend command fails.
#lvextend vg/stripe1 -L 406GUsing stripesize of last segment 64.00 KB Extending logical volume stripe1 to 406.00 GB Insufficient suitable allocatable extents for logical volume stripe1: 34480 more required #lvextend -i1 -l+100%FREE vg/stripe1
lvreduce command to shrink the volume. After shrinking the volume, remount the file system.
lvol1 in volume group vg00 by 3 logical extents.
lvreduce -l -3 vg00/lvol1
vgscan command is run to
scan the block devices on the system looking for LVM labels, to
determine which of them are physical volumes and to read the metadata
and build up a list of volume groups. The names of the physical volumes
are stored in the cache file of each node in the system, /etc/lvm/.cache. Subsequent commands may read that file to avoiding rescanning.
lvm.conf configuration file. The filters in the lvm.conf file consist of a series of simple regular expressions that get applied to the device names that are in the /dev directory to decide whether to accept or reject each block device found.
a/loop/ is equivalent to a/.*loop.*/ and would match /dev/solooperation/lvol1.
filter = [ "a/.*/" ]
filter = [ "r|/dev/cdrom|" ]
filter = [ "a/loop.*/", "r/.*/" ]
filter =[ "a|loop.*|", "a|/dev/hd.*|", "r|.*|" ]
filter = [ "a|^/dev/hda8$|", "r/.*/" ]
lvm.conf file, see Appendix B, The LVM Configuration Files and the lvm.conf(5) man page.
pvmove command.
pvmove command breaks up the data to
be moved into sections and creates a temporary mirror to move each
section. For more information on the operation of the pvmove command, see the pvmove(8) man page.
/dev/sdc1 to other free physical volumes in the volume group:
pvmove /dev/sdc1
MyLV.
pvmove -n MyLV /dev/sdc1
pvmove command can take a long
time to execute, you may want to run the command in the background to
avoid display of progress updates in the foreground. The following
command moves all extents allocated to to the physical volume /dev/sdc1 over to /dev/sdf1 in the background.
pvmove -b /dev/sdc1 /dev/sdf1
pvmove -i5 /dev/sdd1
lvchange -aey command. Alternatively, you can use lvchange -aly
command to activate logical volumes only on the local node but not
exclusively. You can later activate them on additional nodes
concurrently.
pvs, lvs, and vgs
commands. The reports that these commands generate include one line of
output for each object. Each line contains an ordered list of fields of
properties related to the object. There are five ways to select the
objects to be reported: by physical volume, volume group, logical
volume, physical volume segment, and logical volume segment.
pvs, lvs, or vgs
command determines the default set of fields displayed and the sort
order. You can control the output of these commands with the following
arguments:
-o argument. For example, the following output is the default display for the pvs command (which displays information about physical volumes).
# pvs
PV VG Fmt Attr PSize PFree
/dev/sdb1 new_vg lvm2 a- 17.14G 17.14G
/dev/sdc1 new_vg lvm2 a- 17.14G 17.09G
/dev/sdd1 new_vg lvm2 a- 17.14G 17.14G
# pvs -o pv_name,pv_size
PV PSize
/dev/sdb1 17.14G
/dev/sdc1 17.14G
/dev/sdd1 17.14G
# pvs -o +pv_uuid
PV VG Fmt Attr PSize PFree PV UUID
/dev/sdb1 new_vg lvm2 a- 17.14G 17.14G onFF2w-1fLC-ughJ-D9eB-M7iv-6XqA-dqGeXY
/dev/sdc1 new_vg lvm2 a- 17.14G 17.09G Joqlch-yWSj-kuEn-IdwM-01S9-X08M-mcpsVe
/dev/sdd1 new_vg lvm2 a- 17.14G 17.14G yvfvZK-Cf31-j75k-dECm-0RZ3-0dGW-UqkCS
-v argument to a command includes some extra fields. For example, the pvs -v command will display the DevSize and PV UUID fields in addition to the default fields.
# pvs -v
Scanning for physical volume names
PV VG Fmt Attr PSize PFree DevSize PV UUID
/dev/sdb1 new_vg lvm2 a- 17.14G 17.14G 17.14G onFF2w-1fLC-ughJ-D9eB-M7iv-6XqA-dqGeXY
/dev/sdc1 new_vg lvm2 a- 17.14G 17.09G 17.14G Joqlch-yWSj-kuEn-IdwM-01S9-XO8M-mcpsVe
/dev/sdd1 new_vg lvm2 a- 17.14G 17.14G 17.14G yvfvZK-Cf31-j75k-dECm-0RZ3-0dGW-tUqkCS
--noheadings argument suppresses the headings line. This can be useful for writing scripts.
--noheadings argument in combination with the pv_name argument, which will generate a list of all physical volumes.
# pvs --noheadings -o pv_name
/dev/sdb1
/dev/sdc1
/dev/sdd1
--separator separator argument uses separator to separate each field.
pvs command with an equals sign (=).
# pvs --separator =
PV=VG=Fmt=Attr=PSize=PFree
/dev/sdb1=new_vg=lvm2=a-=17.14G=17.14G
/dev/sdc1=new_vg=lvm2=a-=17.14G=17.09G
/dev/sdd1=new_vg=lvm2=a-=17.14G=17.14G
separator argument, use the separator argument in conjunction with the --aligned argument.
# pvs --separator = --aligned
PV =VG =Fmt =Attr=PSize =PFree
/dev/sdb1 =new_vg=lvm2=a- =17.14G=17.14G
/dev/sdc1 =new_vg=lvm2=a- =17.14G=17.09G
/dev/sdd1 =new_vg=lvm2=a- =17.14G=17.14G
-P argument of the lvs or vgs
command to display information about a failed volume that would
otherwise not appear in the output. For information on the output this
argument yields, see Section 6.2, “Displaying Information on Failed Devices”.
pvs(8), vgs(8) and lvs(8) man pages.
# vgs -o +pv_name
VG #PV #LV #SN Attr VSize VFree PV
new_vg 3 1 0 wz--n- 51.42G 51.37G /dev/sdc1
new_vg 3 1 0 wz--n- 51.42G 51.37G /dev/sdd1
new_vg 3 1 0 wz--n- 51.42G 51.37G /dev/sdb1
pvs, vgs, and lvs commands.
pvs command, name means pv_name, but with the vgs command, name is interpreted as vg_name.
pvs -o pv_free.
# pvs -o +free
PFree
17.14G
17.09G
17.14G
pvs command, along with the field name as it appears in the header display and a description of the field.
| Argument | Header | Description |
|---|---|---|
dev_size
| DevSize | The size of the underlying device on which the physical volume was created |
pe_start
| 1st PE | Offset to the start of the first physical extent in the underlying device |
pv_attr
| Attr | Status of the physical volume: (a)llocatable or e(x)ported. |
pv_fmt
| Fmt |
The metadata format of the physical volume (lvm2 or lvm1)
|
pv_free
| PFree | The free space remaining on the physical volume |
pv_name
| PV | The physical volume name |
pv_pe_alloc_count
| Alloc | Number of used physical extents |
pv_pe_count
| PE | Number of physical extents |
pvseg_size
| SSize | The segment size of the physical volume |
pvseg_start
| Start | The starting physical extent of the physical volume segment |
pv_size
| PSize | The size of the physical volume |
pv_tags
| PV Tags | LVM tags attached to the physical volume |
pv_used
| Used | The amount of space currently used on the physical volume |
pv_uuid
| PV UUID | The UUID of the physical volume |
pvs command displays the following fields by default: pv_name, vg_name, pv_fmt, pv_attr, pv_size, pv_free. The display is sorted by pv_name.
# pvs
PV VG Fmt Attr PSize PFree
/dev/sdb1 new_vg lvm2 a- 17.14G 17.14G
/dev/sdc1 new_vg lvm2 a- 17.14G 17.09G
/dev/sdd1 new_vg lvm2 a- 17.14G 17.13G
-v argument with the pvs command adds the following fields to the default display: dev_size, pv_uuid.
# pvs -v
Scanning for physical volume names
PV VG Fmt Attr PSize PFree DevSize PV UUID
/dev/sdb1 new_vg lvm2 a- 17.14G 17.14G 17.14G onFF2w-1fLC-ughJ-D9eB-M7iv-6XqA-dqGeXY
/dev/sdc1 new_vg lvm2 a- 17.14G 17.09G 17.14G Joqlch-yWSj-kuEn-IdwM-01S9-XO8M-mcpsVe
/dev/sdd1 new_vg lvm2 a- 17.14G 17.13G 17.14G yvfvZK-Cf31-j75k-dECm-0RZ3-0dGW-tUqkCS
--segments argument of the pvs
command to display information about each physical volume segment. A
segment is a group of extents. A segment view can be useful if you want
to see whether your logical volume is fragmented.
pvs --segments command displays the following fields by default: pv_name, vg_name, pv_fmt, pv_attr, pv_size, pv_free, pvseg_start, pvseg_size. The display is sorted by pv_name and pvseg_size within the physical volume.
# pvs --segments
PV VG Fmt Attr PSize PFree Start SSize
/dev/hda2 VolGroup00 lvm2 a- 37.16G 32.00M 0 1172
/dev/hda2 VolGroup00 lvm2 a- 37.16G 32.00M 1172 16
/dev/hda2 VolGroup00 lvm2 a- 37.16G 32.00M 1188 1
/dev/sda1 vg lvm2 a- 17.14G 16.75G 0 26
/dev/sda1 vg lvm2 a- 17.14G 16.75G 26 24
/dev/sda1 vg lvm2 a- 17.14G 16.75G 50 26
/dev/sda1 vg lvm2 a- 17.14G 16.75G 76 24
/dev/sda1 vg lvm2 a- 17.14G 16.75G 100 26
/dev/sda1 vg lvm2 a- 17.14G 16.75G 126 24
/dev/sda1 vg lvm2 a- 17.14G 16.75G 150 22
/dev/sda1 vg lvm2 a- 17.14G 16.75G 172 4217
/dev/sdb1 vg lvm2 a- 17.14G 17.14G 0 4389
/dev/sdc1 vg lvm2 a- 17.14G 17.14G 0 4389
/dev/sdd1 vg lvm2 a- 17.14G 17.14G 0 4389
/dev/sde1 vg lvm2 a- 17.14G 17.14G 0 4389
/dev/sdf1 vg lvm2 a- 17.14G 17.14G 0 4389
/dev/sdg1 vg lvm2 a- 17.14G 17.14G 0 4389
pvs -a command to see devices detected by LVM that have not been initialized as LVM physical volumes.
# pvs -a
PV VG Fmt Attr PSize PFree
/dev/VolGroup00/LogVol01 -- 0 0
/dev/new_vg/lvol0 -- 0 0
/dev/ram -- 0 0
/dev/ram0 -- 0 0
/dev/ram2 -- 0 0
/dev/ram3 -- 0 0
/dev/ram4 -- 0 0
/dev/ram5 -- 0 0
/dev/ram6 -- 0 0
/dev/root -- 0 0
/dev/sda -- 0 0
/dev/sdb -- 0 0
/dev/sdb1 new_vg lvm2 a- 17.14G 17.14G
/dev/sdc -- 0 0
/dev/sdc1 new_vg lvm2 a- 17.14G 17.09G
/dev/sdd -- 0 0
/dev/sdd1 new_vg lvm2 a- 17.14G 17.14G
vgs command, along with the field name as it appears in the header display and a description of the field.
| Argument | Header | Description |
|---|---|---|
lv_count
| #LV | The number of logical volumes the volume group contains |
max_lv
| MaxLV | The maximum number of logical volumes allowed in the volume group (0 if unlimited) |
max_pv
| MaxPV | The maximum number of physical volumes allowed in the volume group (0 if unlimited) |
pv_count
| #PV | The number of physical volumes that define the volume group |
snap_count
| #SN | The number of snapshots the volume group contains |
vg_attr
| Attr | Status of the volume group: (w)riteable, (r)eadonly, resi(z)eable, e(x)ported, (p)artial and (c)lustered. |
vg_extent_count
| #Ext | The number of physical extents in the volume group |
vg_extent_size
| Ext | The size of the physical extents in the volume group |
vg_fmt
| Fmt |
The metadata format of the volume group (lvm2 or lvm1)
|
vg_free
| VFree | Size of the free space remaining in the volume group |
vg_free_count
| Free | Number of free physical extents in the volume group |
vg_name
| VG | The volume group name |
vg_seqno
| Seq | Number representing the revision of the volume group |
vg_size
| VSize | The size of the volume group |
vg_sysid
| SYS ID | LVM1 System ID |
vg_tags
| VG Tags | LVM tags attached to the volume group |
vg_uuid
| VG UUID | The UUID of the volume group |
vgs command displays the following fields by default: vg_name, pv_count, lv_count, snap_count, vg_attr, vg_size, vg_free. The display is sorted by vg_name.
# vgs
VG #PV #LV #SN Attr VSize VFree
new_vg 3 1 1 wz--n- 51.42G 51.36G
-v argument with the vgs command adds the following fields to the default display: vg_extent_size, vg_uuid.
# vgs -v
Finding all volume groups
Finding volume group "new_vg"
VG Attr Ext #PV #LV #SN VSize VFree VG UUID
new_vg wz--n- 4.00M 3 1 1 51.42G 51.36G jxQJ0a-ZKk0-OpMO-0118-nlwO-wwqd-fD5D32
lvs command, along with the field name as it appears in the header display and a description of the field.
| Argument | Header | Description | ||||||
|---|---|---|---|---|---|---|---|---|
| Chunk | Unit size in a snapshot volume | ||||||
copy_percent
| Copy% |
The synchronization percentage of a mirrored logical volume; also used when physical extents are being moved with the pv_move command
| ||||||
devices
| Devices | The underlying devices that make up the logical volume: the physical volumes, logical volumes, and start physical extents and logical extents | ||||||
lv_attr
| Attr |
The status of the logical volume. The logical volume attribute bits are as follows:
| ||||||
lv_kernel_major
| KMaj | Actual major device number of the logical volume (-1 if inactive) | ||||||
lv_kernel_minor
| KMIN | Actual minor device number of the logical volume (-1 if inactive) | ||||||
lv_major
| Maj | The persistent major device number of the logical volume (-1 if not specified) | ||||||
lv_minor
| Min | The persistent minor device number of the logical volume (-1 if not specified) | ||||||
lv_name
| LV | The name of the logical volume | ||||||
lv_size
| LSize | The size of the logical volume | ||||||
lv_tags
| LV Tags | LVM tags attached to the logical volume | ||||||
lv_uuid
| LV UUID | The UUID of the logical volume. | ||||||
mirror_log
| Log | Device on which the mirror log resides | ||||||
modules
| Modules | Corresponding kernel device-mapper target necessary to use this logical volume | ||||||
move_pv
| Move |
Source physical volume of a temporary logical volume created with the pvmove command
| ||||||
origin
| Origin | The origin device of a snapshot volume | ||||||
| Region | The unit size of a mirrored logical volume | ||||||
seg_count
| #Seg | The number of segments in the logical volume | ||||||
seg_size
| SSize | The size of the segments in the logical volume | ||||||
seg_start
| Start | Offset of the segment in the logical volume | ||||||
seg_tags
| Seg Tags | LVM tags attached to the segments of the logical volume | ||||||
segtype
| Type | The segment type of a logical volume (for example: mirror, striped, linear) | ||||||
snap_percent
| Snap% | Current percentage of a snapshot volume that is in use | ||||||
stripes
| #Str | Number of stripes or mirrors in a logical volume | ||||||
| Stripe | Unit size of the stripe in a striped logical volume |
lvs command displays the following fields by default: lv_name, vg_name, lv_attr, lv_size, origin, snap_percent, move_pv, mirror_log, copy_percent. The default display is sorted by vg_name and lv_name within the volume group.
# lvs
LV VG Attr LSize Origin Snap% Move Log Copy%
lvol0 new_vg owi-a- 52.00M
newvgsnap1 new_vg swi-a- 8.00M lvol0 0.20
-v argument with the lvs command adds the following fields to the default display: seg_count, lv_major, lv_minor, lv_kernel_major, lv_kernel_minor, lv_uuid.
# lvs -v
Finding all logical volumes
LV VG #Seg Attr LSize Maj Min KMaj KMin Origin Snap% Move Copy% Log LV UUID
lvol0 new_vg 1 owi-a- 52.00M -1 -1 253 3 LBy1Tz-sr23-OjsI-LT03-nHLC-y8XW-EhCl78
newvgsnap1 new_vg 1 swi-a- 8.00M -1 -1 253 5 lvol0 0.20 1ye1OU-1cIu-o79k-20h2-ZGF0-qCJm-CfbsIx
--segments argument of the lvs command to display information with default columns that emphasize the segment information. When you use the segments argument, the seg prefix is optional. The lvs --segments command displays the following fields by default: lv_name, vg_name, lv_attr, stripes, segtype, seg_size. The default display is sorted by vg_name, lv_name within the volume group, and seg_start within the logical volume. If the logical volumes were fragmented, the output from this command would show that.
# lvs --segments
LV VG Attr #Str Type SSize
LogVol00 VolGroup00 -wi-ao 1 linear 36.62G
LogVol01 VolGroup00 -wi-ao 1 linear 512.00M
lv vg -wi-a- 1 linear 104.00M
lv vg -wi-a- 1 linear 104.00M
lv vg -wi-a- 1 linear 104.00M
lv vg -wi-a- 1 linear 88.00M
-v argument with the lvs --segments command adds the following fields to the default display: seg_start, stripesize, chunksize.
# lvs -v --segments
Finding all logical volumes
LV VG Attr Start SSize #Str Type Stripe Chunk
lvol0 new_vg owi-a- 0 52.00M 1 linear 0 0
newvgsnap1 new_vg swi-a- 0 8.00M 1 linear 0 8.00K
lvs command on a system with one logical volume configured, followed by the default output of the lvs command with the segments argument specified.
#lvsLV VG Attr LSize Origin Snap% Move Log Copy% lvol0 new_vg -wi-a- 52.00M #lvs --segmentsLV VG Attr #Str Type SSize lvol0 new_vg -wi-a- 1 linear 52.00M
lvs, vgs, or pvs command has to be generated and stored internally before it can be sorted and columns aligned correctly. You can specify the --unbuffered argument to display unsorted output as soon as it is generated.
-O argument of any of the reporting commands. It is not necessary to include these fields within the output itself.
pvs command that displays the physical volume name, size, and free space.
# pvs -o pv_name,pv_size,pv_free
PV PSize PFree
/dev/sdb1 17.14G 17.14G
/dev/sdc1 17.14G 17.09G
/dev/sdd1 17.14G 17.14G
# pvs -o pv_name,pv_size,pv_free -O pv_free
PV PSize PFree
/dev/sdc1 17.14G 17.09G
/dev/sdd1 17.14G 17.14G
/dev/sdb1 17.14G 17.14G
# pvs -o pv_name,pv_size -O pv_free
PV PSize
/dev/sdc1 17.14G
/dev/sdd1 17.14G
/dev/sdb1 17.14G
-O argument with the - character.
# pvs -o pv_name,pv_size,pv_free -O -pv_free
PV PSize PFree
/dev/sdd1 17.14G 17.14G
/dev/sdb1 17.14G 17.14G
/dev/sdc1 17.14G 17.09G
--units
argument of the report command. You can specify (b)ytes, (k)ilobytes,
(m)egabytes, (g)igabytes, (t)erabytes, (e)xabytes, (p)etabytes, and
(h)uman-readable. The default display is human-readable. You can
override the default by setting the units parameter in the global section of the lvm.conf file.
pvs command in megabytes rather than the default gigabytes.
# pvs --units m
PV VG Fmt Attr PSize PFree
/dev/sda1 lvm2 -- 17555.40M 17555.40M
/dev/sdb1 new_vg lvm2 a- 17552.00M 17552.00M
/dev/sdc1 new_vg lvm2 a- 17552.00M 17500.00M
/dev/sdd1 new_vg lvm2 a- 17552.00M 17552.00M
# pvs
PV VG Fmt Attr PSize PFree
/dev/sdb1 new_vg lvm2 a- 17.14G 17.14G
/dev/sdc1 new_vg lvm2 a- 17.14G 17.09G
/dev/sdd1 new_vg lvm2 a- 17.14G 17.14G
# pvs --units G
PV VG Fmt Attr PSize PFree
/dev/sdb1 new_vg lvm2 a- 18.40G 18.40G
/dev/sdc1 new_vg lvm2 a- 18.40G 18.35G
/dev/sdd1 new_vg lvm2 a- 18.40G 18.40G
pvs command as a number of sectors.
# pvs --units s
PV VG Fmt Attr PSize PFree
/dev/sdb1 new_vg lvm2 a- 35946496S 35946496S
/dev/sdc1 new_vg lvm2 a- 35946496S 35840000S
/dev/sdd1 new_vg lvm2 a- 35946496S 35946496S
pvs command in units of 4 megabytes.
# pvs --units 4m
PV VG Fmt Attr PSize PFree
/dev/sdb1 new_vg lvm2 a- 4388.00U 4388.00U
/dev/sdc1 new_vg lvm2 a- 4388.00U 4375.00U
/dev/sdd1 new_vg lvm2 a- 4388.00U 4388.00U
new_logical_volume that consists of the disks at /dev/sda1, /dev/sdb1, and /dev/sdc1.
/dev/sda1, /dev/sdb1, and /dev/sdc1.
[root@tng3-1 ~]# pvcreate /dev/sda1 /dev/sdb1 /dev/sdc1
Physical volume "/dev/sda1" successfully created
Physical volume "/dev/sdb1" successfully created
Physical volume "/dev/sdc1" successfully created
new_vol_group.
[root@tng3-1 ~]# vgcreate new_vol_group /dev/sda1 /dev/sdb1 /dev/sdc1
Volume group "new_vol_group" successfully created
vgs command to display the attributes of the new volume group.
[root@tng3-1 ~]# vgs
VG #PV #LV #SN Attr VSize VFree
new_vol_group 3 0 0 wz--n- 51.45G 51.45G
new_logical_volume from the volume group new_vol_group. This example creates a logical volume that uses 2GB of the volume group.
[root@tng3-1 ~]# lvcreate -L2G -n new_logical_volume new_vol_group
Logical volume "new_logical_volume" created
[root@tng3-1 ~]#mkfs.gfs2 -plock_nolock -j 1 /dev/new_vol_group/new_logical_volumeThis will destroy any data on /dev/new_vol_group/new_logical_volume. Are you sure you want to proceed? [y/n]yDevice: /dev/new_vol_group/new_logical_volume Blocksize: 4096 Filesystem Size: 491460 Journals: 1 Resource Groups: 8 Locking Protocol: lock_nolock Lock Table: Syncing... All Done
[root@tng3-1 ~]#mount /dev/new_vol_group/new_logical_volume /mnt[root@tng3-1 ~]#dfFilesystem 1K-blocks Used Available Use% Mounted on /dev/new_vol_group/new_logical_volume 1965840 20 1965820 1% /mnt
striped_logical_volume that stripes data across the disks at /dev/sda1, /dev/sdb1, and /dev/sdc1.
/dev/sda1, /dev/sdb1, and /dev/sdc1.
[root@tng3-1 ~]# pvcreate /dev/sda1 /dev/sdb1 /dev/sdc1
Physical volume "/dev/sda1" successfully created
Physical volume "/dev/sdb1" successfully created
Physical volume "/dev/sdc1" successfully created
volgroup01.
[root@tng3-1 ~]# vgcreate volgroup01 /dev/sda1 /dev/sdb1 /dev/sdc1
Volume group "volgroup01" successfully created
vgs command to display the attributes of the new volume group.
[root@tng3-1 ~]# vgs
VG #PV #LV #SN Attr VSize VFree
volgroup01 3 0 0 wz--n- 51.45G 51.45G
striped_logical_volume from the volume group volgroup01. This example creates a logical volume that is 2 gigabytes in size, with three stripes and a stripe size of 4 kilobytes.
[root@tng3-1 ~]# lvcreate -i3 -I4 -L2G -nstriped_logical_volume volgroup01
Rounding size (512 extents) up to stripe boundary size (513 extents)
Logical volume "striped_logical_volume" created
[root@tng3-1 ~]#mkfs.gfs2 -plock_nolock -j 1 /dev/volgroup01/striped_logical_volumeThis will destroy any data on /dev/volgroup01/striped_logical_volume. Are you sure you want to proceed? [y/n]yDevice: /dev/volgroup01/striped_logical_volume Blocksize: 4096 Filesystem Size: 492484 Journals: 1 Resource Groups: 8 Locking Protocol: lock_nolock Lock Table: Syncing... All Done
[root@tng3-1 ~]#mount /dev/volgroup01/striped_logical_volume /mnt[root@tng3-1 ~]#dfFilesystem 1K-blocks Used Available Use% Mounted on /dev/mapper/VolGroup00-LogVol00 13902624 1656776 11528232 13% / /dev/hda1 101086 10787 85080 12% /boot tmpfs 127880 0 127880 0% /dev/shm /dev/volgroup01/striped_logical_volume 1969936 20 1969916 1% /mnt
mylv is carved from the volume group myvol, which in turn consists of the three physical volumes, /dev/sda1, /dev/sdb1, and /dev/sdc1.
myvg will consist of /dev/sda1 and /dev/sdb1. A second volume group, yourvg, will consist of /dev/sdc1.
pvscan command to determine how much free space is currently available in the volume group.
[root@tng3-1 ~]# pvscan
PV /dev/sda1 VG myvg lvm2 [17.15 GB / 0 free]
PV /dev/sdb1 VG myvg lvm2 [17.15 GB / 12.15 GB free]
PV /dev/sdc1 VG myvg lvm2 [17.15 GB / 15.80 GB free]
Total: 3 [51.45 GB] / in use: 3 [51.45 GB] / in no VG: 0 [0 ]
/dev/sdc1 to /dev/sdb1 with the pvmove command. The pvmove command can take a long time to execute.
[root@tng3-1 ~]# pvmove /dev/sdc1 /dev/sdb1
/dev/sdc1: Moved: 14.7%
/dev/sdc1: Moved: 30.3%
/dev/sdc1: Moved: 45.7%
/dev/sdc1: Moved: 61.0%
/dev/sdc1: Moved: 76.6%
/dev/sdc1: Moved: 92.2%
/dev/sdc1: Moved: 100.0%
/dev/sdc1 is free.
[root@tng3-1 ~]# pvscan
PV /dev/sda1 VG myvg lvm2 [17.15 GB / 0 free]
PV /dev/sdb1 VG myvg lvm2 [17.15 GB / 10.80 GB free]
PV /dev/sdc1 VG myvg lvm2 [17.15 GB / 17.15 GB free]
Total: 3 [51.45 GB] / in use: 3 [51.45 GB] / in no VG: 0 [0 ]
yourvg, use the vgsplit command to split the volume group myvg.
lvchange command or the vgchange command. The following command deactivates the logical volume mylv and then splits the volume group yourvg from the volume group myvg, moving the physical volume /dev/sdc1 into the new volume group yourvg.
[root@tng3-1 ~]#lvchange -a n /dev/myvg/mylv[root@tng3-1 ~]#vgsplit myvg yourvg /dev/sdc1Volume group "yourvg" successfully split from "myvg"
vgs command to see the attributes of the two volume groups.
[root@tng3-1 ~]# vgs
VG #PV #LV #SN Attr VSize VFree
myvg 2 1 0 wz--n- 34.30G 10.80G
yourvg 1 0 0 wz--n- 17.15G 17.15G
yourlv.
[root@tng3-1 ~]# lvcreate -L5G -n yourlv yourvg
Logical volume "yourlv" created
[root@tng3-1 ~]#mkfs.gfs2 -plock_nolock -j 1 /dev/yourvg/yourlvThis will destroy any data on /dev/yourvg/yourlv. Are you sure you want to proceed? [y/n]yDevice: /dev/yourvg/yourlv Blocksize: 4096 Filesystem Size: 1277816 Journals: 1 Resource Groups: 20 Locking Protocol: lock_nolock Lock Table: Syncing... All Done [root@tng3-1 ~]#mount /dev/yourvg/yourlv /mnt
mylv, you need to activate it again before you can mount it.
root@tng3-1 ~]#lvchange -a y mylv[root@tng3-1 ~]#mount /dev/myvg/mylv /mnt[root@tng3-1 ~]#dfFilesystem 1K-blocks Used Available Use% Mounted on /dev/yourvg/yourlv 24507776 32 24507744 1% /mnt /dev/myvg/mylv 24507776 32 24507744 1% /mnt
myvg.
[root@tng3-1]# pvs -o+pv_used
PV VG Fmt Attr PSize PFree Used
/dev/sda1 myvg lvm2 a- 17.15G 12.15G 5.00G
/dev/sdb1 myvg lvm2 a- 17.15G 12.15G 5.00G
/dev/sdc1 myvg lvm2 a- 17.15G 12.15G 5.00G
/dev/sdd1 myvg lvm2 a- 17.15G 2.15G 15.00G
/dev/sdb1 so that we can remove it from the volume group.
pvmove command on the device you want to remove with no other options and the extents will be distributed to the other devices.
[root@tng3-1 ~]# pvmove /dev/sdb1
/dev/sdb1: Moved: 2.0%
...
/dev/sdb1: Moved: 79.2%
...
/dev/sdb1: Moved: 100.0%
pvmove command has finished executing, the distribution of extents is as follows:
[root@tng3-1]# pvs -o+pv_used
PV VG Fmt Attr PSize PFree Used
/dev/sda1 myvg lvm2 a- 17.15G 7.15G 10.00G
/dev/sdb1 myvg lvm2 a- 17.15G 17.15G 0
/dev/sdc1 myvg lvm2 a- 17.15G 12.15G 5.00G
/dev/sdd1 myvg lvm2 a- 17.15G 2.15G 15.00G
vgreduce command to remove the physical volume /dev/sdb1 from the volume group.
[root@tng3-1 ~]# vgreduce myvg /dev/sdb1
Removed "/dev/sdb1" from volume group "myvg"
[root@tng3-1 ~]# pvs
PV VG Fmt Attr PSize PFree
/dev/sda1 myvg lvm2 a- 17.15G 7.15G
/dev/sdb1 lvm2 -- 17.15G 17.15G
/dev/sdc1 myvg lvm2 a- 17.15G 12.15G
/dev/sdd1 myvg lvm2 a- 17.15G 2.15G
myvg as follows:
[root@tng3-1]# pvs -o+pv_used
PV VG Fmt Attr PSize PFree Used
/dev/sda1 myvg lvm2 a- 17.15G 7.15G 10.00G
/dev/sdb1 myvg lvm2 a- 17.15G 15.15G 2.00G
/dev/sdc1 myvg lvm2 a- 17.15G 15.15G 2.00G
/dev/sdb1 to a new device, /dev/sdd1.
/dev/sdd1.
[root@tng3-1 ~]# pvcreate /dev/sdd1
Physical volume "/dev/sdd1" successfully created
/dev/sdd1 to the existing volume group myvg.
[root@tng3-1 ~]#vgextend myvg /dev/sdd1Volume group "myvg" successfully extended [root@tng3-1]#pvs -o+pv_usedPV VG Fmt Attr PSize PFree Used /dev/sda1 myvg lvm2 a- 17.15G 7.15G 10.00G /dev/sdb1 myvg lvm2 a- 17.15G 15.15G 2.00G /dev/sdc1 myvg lvm2 a- 17.15G 15.15G 2.00G /dev/sdd1 myvg lvm2 a- 17.15G 17.15G 0
pvmove command to move the data from /dev/sdb1 to /dev/sdd1.
[root@tng3-1 ~]#pvmove /dev/sdb1 /dev/sdd1/dev/sdb1: Moved: 10.0% ... /dev/sdb1: Moved: 79.7% ... /dev/sdb1: Moved: 100.0% [root@tng3-1]#pvs -o+pv_usedPV VG Fmt Attr PSize PFree Used /dev/sda1 myvg lvm2 a- 17.15G 7.15G 10.00G /dev/sdb1 myvg lvm2 a- 17.15G 17.15G 0 /dev/sdc1 myvg lvm2 a- 17.15G 15.15G 2.00G /dev/sdd1 myvg lvm2 a- 17.15G 15.15G 2.00G
/dev/sdb1, you can remove it from the volume group.
[root@tng3-1 ~]# vgreduce myvg /dev/sdb1
Removed "/dev/sdb1" from volume group "myvg"
lvm.conf file must be set correctly to enable cluster locking, either directly or by means of the lvmconf command as described in Section 3.1, “Creating LVM Volumes in a Cluster”.
lvm.conf file in every node of the
cluster. By default, the locking type is set to local. To change this,
execute the following command in each node of the cluster to enable
clustered locking:
# /sbin/lvmconf --enable-clusterclvmd daemon is running on the node from which it was issued:
[root@doc-07 ~]# ps auxw | grep clvmd
root 17642 0.0 0.1 32164 1072 ? Ssl Apr06 0:00 clvmd -T20 -t 90
[root@example-01 ~]# cman_tool services
fence domain
member count 3
victim count 0
victim now 0
master nodeid 2
wait state none
members 1 2 3
dlm lockspaces
name clvmd
id 0x4104eefa
flags 0x00000000
change member 3 joined 1 remove 0 failed 0 seq 1,1
members 1 2 3
cmirror package is installed.
cmirrord service.
[root@hexample-01 ~]# service cmirrord start
Starting cmirrord: [ OK ]
[root@doc-07 ~]#pvcreate /dev/xvdb1Physical volume "/dev/xvdb1" successfully created [root@doc-07 ~]#pvcreate /dev/xvdb2Physical volume "/dev/xvdb2" successfully created [root@doc-07 ~]#pvcreate /dev/xvdc1Physical volume "/dev/xvdc1" successfully created
vg001 that consists of the three physical volumes that were created in the previous step.
[root@doc-07 ~]# vgcreate vg001 /dev/xvdb1 /dev/xvdb2 /dev/xvdc1
Clustered volume group "vg001" successfully created
vgcreate command indicates that the volume group is clustered. You can verify that a volume group is clustered with the vgs command, which will show the volume group's attributes. If a volume group is clustered, it will show a c attribute.
[root@doc-07 ~]# vgs vg001
VG #PV #LV #SN Attr VSize VFree
vg001 3 0 0 wz--nc 68.97G 68.97G
mirrorlv from the volume group vg001.
This volume has one mirror leg. This example specifies which extents of
the physical volume will be used for the logical volume.
[root@doc-07 ~]# lvcreate -l 1000 -m1 vg001 -n mirrorlv /dev/xvdb1:1-1000 /dev/xvdb2:1-1000 /dev/xvdc1:0
Logical volume "mirrorlv" created
lvs command to display
the progress of the mirror creation. The following example shows that
the mirror is 47% synced, then 91% synced, then 100% synced when the
mirror is complete.
[root@doc-07 log]#lvs vg001/mirrorlvLV VG Attr LSize Origin Snap% Move Log Copy% Convert mirrorlv vg001 mwi-a- 3.91G vg001_mlog 47.00 [root@doc-07 log]#lvs vg001/mirrorlvLV VG Attr LSize Origin Snap% Move Log Copy% Convert mirrorlv vg001 mwi-a- 3.91G vg001_mlog 91.00 [root@doc-07 ~]#lvs vg001/mirrorlvLV VG Attr LSize Origin Snap% Move Log Copy% Convert mirrorlv vg001 mwi-a- 3.91G vg001_mlog 100.00
May 10 14:52:52 doc-07 [19402]: Monitoring mirror device vg001-mirrorlv for events May 10 14:55:00 doc-07 lvm[19402]: vg001-mirrorlv is now in-sync
lvs with the -o +devices
options to display the configuration of the mirror, including which
devices make up the mirror legs. You can see that the logical volume in
this example is composed of two linear images and one log.
[root@doc-07 ~]# lvs -a -o +devices
LV VG Attr LSize Origin Snap% Move Log Copy% Convert Devices
mirrorlv vg001 mwi-a- 3.91G mirrorlv_mlog 100.00 mirrorlv_mimage_0(0),mirrorlv_mimage_1(0)
[mirrorlv_mimage_0] vg001 iwi-ao 3.91G /dev/xvdb1(1)
[mirrorlv_mimage_1] vg001 iwi-ao 3.91G /dev/xvdb2(1)
[mirrorlv_mlog] vg001 lwi-ao 4.00M /dev/xvdc1(0)
seg_pe_ranges option of the lvs
to display the data layout. You can use this option to verify that your
layout is properly redundant. The output of this command displays PE
ranges in the same format that the lvcreate and lvresize commands take as input.
[root@doc-07 ~]# lvs -a -o +seg_pe_ranges --segments
PE Ranges
mirrorlv_mimage_0:0-999 mirrorlv_mimage_1:0-999
/dev/xvdb1:1-1000
/dev/xvdb2:1-1000
/dev/xvdc1:0-0
-v, -vv, -vvv, or -vvvv argument of any command for increasingly verbose levels of output.
-vvvv argument. After
you have finished examining this output be sure to reset this parameter
to 0, to avoid possible problems with the machine locking during low
memory situations.
lvmdump command, which provides an information dump for diagnostic purposes. For information, see the lvmdump(8) man page.
lvs -v, pvs -a or dmsetup info -c command for additional system information.
/etc/lvm/backup file and archived versions in the /etc/lvm/archive file.
lvm dumpconfig command.
.cache file in the /etc/lvm directory for a record of which devices have physical volumes on them.
-P argument of the lvs or vgs
command to display information about a failed volume that would
otherwise not appear in the output. This argument permits some
operations even though the metadata is not completely consistent
internally. For example, if one of the devices that made up the volume
group vg failed, the vgs command might show the following output.
[root@link-07 tmp]# vgs -o +devices
Volume group "vg" not found
-P argument of the vgs command, the volume group is still unusable but you can see more information about the failed device.
[root@link-07 tmp]# vgs -P -o +devices
Partial mode. Incomplete volume groups will be activated read-only.
VG #PV #LV #SN Attr VSize VFree Devices
vg 9 2 0 rz-pn- 2.11T 2.07T unknown device(0)
vg 9 2 0 rz-pn- 2.11T 2.07T unknown device(5120),/dev/sda1(0)
lvs command without the -P argument shows the following output.
[root@link-07 tmp]# lvs -a -o +devices
Volume group "vg" not found
-P argument shows the logical volumes that have failed.
[root@link-07 tmp]# lvs -P -a -o +devices
Partial mode. Incomplete volume groups will be activated read-only.
LV VG Attr LSize Origin Snap% Move Log Copy% Devices
linear vg -wi-a- 20.00G unknown device(0)
stripe vg -wi-a- 20.00G unknown device(5120),/dev/sda1(0)
pvs and lvs commands with the -P argument specified when a leg of a mirrored logical volume has failed.
root@link-08 ~]# vgs -a -o +devices -P
Partial mode. Incomplete volume groups will be activated read-only.
VG #PV #LV #SN Attr VSize VFree Devices
corey 4 4 0 rz-pnc 1.58T 1.34T my_mirror_mimage_0(0),my_mirror_mimage_1(0)
corey 4 4 0 rz-pnc 1.58T 1.34T /dev/sdd1(0)
corey 4 4 0 rz-pnc 1.58T 1.34T unknown device(0)
corey 4 4 0 rz-pnc 1.58T 1.34T /dev/sdb1(0)
[root@link-08 ~]# lvs -a -o +devices -P
Partial mode. Incomplete volume groups will be activated read-only.
LV VG Attr LSize Origin Snap% Move Log Copy% Devices
my_mirror corey mwi-a- 120.00G my_mirror_mlog 1.95 my_mirror_mimage_0(0),my_mirror_mimage_1(0)
[my_mirror_mimage_0] corey iwi-ao 120.00G unknown device(0)
[my_mirror_mimage_1] corey iwi-ao 120.00G /dev/sdb1(0)
[my_mirror_mlog] corey lwi-ao 4.00M /dev/sdd1(0)
[root@link-08 ~]# pvcreate /dev/sd[abcdefgh][12]
Physical volume "/dev/sda1" successfully created
Physical volume "/dev/sda2" successfully created
Physical volume "/dev/sdb1" successfully created
Physical volume "/dev/sdb2" successfully created
Physical volume "/dev/sdc1" successfully created
Physical volume "/dev/sdc2" successfully created
Physical volume "/dev/sdd1" successfully created
Physical volume "/dev/sdd2" successfully created
Physical volume "/dev/sde1" successfully created
Physical volume "/dev/sde2" successfully created
Physical volume "/dev/sdf1" successfully created
Physical volume "/dev/sdf2" successfully created
Physical volume "/dev/sdg1" successfully created
Physical volume "/dev/sdg2" successfully created
Physical volume "/dev/sdh1" successfully created
Physical volume "/dev/sdh2" successfully created
vg and the mirrored volume groupfs.
[root@link-08 ~]#vgcreate vg /dev/sd[abcdefgh][12]Volume group "vg" successfully created [root@link-08 ~]#lvcreate -L 750M -n groupfs -m 1 vg /dev/sda1 /dev/sdb1 /dev/sdc1Rounding up size to full physical extent 752.00 MB Logical volume "groupfs" created
lvs command to verify
the layout of the mirrored volume and the underlying devices for the
mirror leg and the mirror log. Note that in the first example the mirror
is not yet completely synced; you should wait until the Copy% field displays 100.00 before continuing.
[root@link-08 ~]#lvs -a -o +devicesLV VG Attr LSize Origin Snap% Move Log Copy% Devices groupfs vg mwi-a- 752.00M groupfs_mlog 21.28 groupfs_mimage_0(0),groupfs_mimage_1(0) [groupfs_mimage_0] vg iwi-ao 752.00M /dev/sda1(0) [groupfs_mimage_1] vg iwi-ao 752.00M /dev/sdb1(0) [groupfs_mlog] vg lwi-ao 4.00M /dev/sdc1(0) [root@link-08 ~]#lvs -a -o +devicesLV VG Attr LSize Origin Snap% Move Log Copy% Devices groupfs vg mwi-a- 752.00M groupfs_mlog 100.00 groupfs_mimage_0(0),groupfs_mimage_1(0) [groupfs_mimage_0] vg iwi-ao 752.00M /dev/sda1(0) [groupfs_mimage_1] vg iwi-ao 752.00M /dev/sdb1(0) [groupfs_mlog] vg lwi-ao 4.00M i /dev/sdc1(0)
/dev/sda1
fails. Any write activity to the mirrored volume causes LVM to detect
the failed mirror. When this occurs, LVM converts the mirror into a
single linear volume. In this case, to trigger the conversion, we
execute a dd command
[root@link-08 ~]# dd if=/dev/zero of=/dev/vg/groupfs count=10
10+0 records in
10+0 records out
lvs command to verify that the device is now a linear device. Because of the failed disk, I/O errors occur.
[root@link-08 ~]# lvs -a -o +devices
/dev/sda1: read failed after 0 of 2048 at 0: Input/output error
/dev/sda2: read failed after 0 of 2048 at 0: Input/output error
LV VG Attr LSize Origin Snap% Move Log Copy% Devices
groupfs vg -wi-a- 752.00M /dev/sdb1(0)
pvcreate command.
[root@link-08 ~]#pvcreate /dev/sda[12]Physical volume "/dev/sda1" successfully created Physical volume "/dev/sda2" successfully created [root@link-08 ~]#pvscanPV /dev/sdb1 VG vg lvm2 [67.83 GB / 67.10 GB free] PV /dev/sdb2 VG vg lvm2 [67.83 GB / 67.83 GB free] PV /dev/sdc1 VG vg lvm2 [67.83 GB / 67.83 GB free] PV /dev/sdc2 VG vg lvm2 [67.83 GB / 67.83 GB free] PV /dev/sdd1 VG vg lvm2 [67.83 GB / 67.83 GB free] PV /dev/sdd2 VG vg lvm2 [67.83 GB / 67.83 GB free] PV /dev/sde1 VG vg lvm2 [67.83 GB / 67.83 GB free] PV /dev/sde2 VG vg lvm2 [67.83 GB / 67.83 GB free] PV /dev/sdf1 VG vg lvm2 [67.83 GB / 67.83 GB free] PV /dev/sdf2 VG vg lvm2 [67.83 GB / 67.83 GB free] PV /dev/sdg1 VG vg lvm2 [67.83 GB / 67.83 GB free] PV /dev/sdg2 VG vg lvm2 [67.83 GB / 67.83 GB free] PV /dev/sdh1 VG vg lvm2 [67.83 GB / 67.83 GB free] PV /dev/sdh2 VG vg lvm2 [67.83 GB / 67.83 GB free] PV /dev/sda1 lvm2 [603.94 GB] PV /dev/sda2 lvm2 [603.94 GB] Total: 16 [2.11 TB] / in use: 14 [949.65 GB] / in no VG: 2 [1.18 TB]
[root@link-08 ~]#vgextend vg /dev/sda[12]Volume group "vg" successfully extended [root@link-08 ~]#pvscanPV /dev/sdb1 VG vg lvm2 [67.83 GB / 67.10 GB free] PV /dev/sdb2 VG vg lvm2 [67.83 GB / 67.83 GB free] PV /dev/sdc1 VG vg lvm2 [67.83 GB / 67.83 GB free] PV /dev/sdc2 VG vg lvm2 [67.83 GB / 67.83 GB free] PV /dev/sdd1 VG vg lvm2 [67.83 GB / 67.83 GB free] PV /dev/sdd2 VG vg lvm2 [67.83 GB / 67.83 GB free] PV /dev/sde1 VG vg lvm2 [67.83 GB / 67.83 GB free] PV /dev/sde2 VG vg lvm2 [67.83 GB / 67.83 GB free] PV /dev/sdf1 VG vg lvm2 [67.83 GB / 67.83 GB free] PV /dev/sdf2 VG vg lvm2 [67.83 GB / 67.83 GB free] PV /dev/sdg1 VG vg lvm2 [67.83 GB / 67.83 GB free] PV /dev/sdg2 VG vg lvm2 [67.83 GB / 67.83 GB free] PV /dev/sdh1 VG vg lvm2 [67.83 GB / 67.83 GB free] PV /dev/sdh2 VG vg lvm2 [67.83 GB / 67.83 GB free] PV /dev/sda1 VG vg lvm2 [603.93 GB / 603.93 GB free] PV /dev/sda2 VG vg lvm2 [603.93 GB / 603.93 GB free] Total: 16 [2.11 TB] / in use: 16 [2.11 TB] / in no VG: 0 [0 ]
[root@link-08 ~]# lvconvert -m 1 /dev/vg/groupfs /dev/sda1 /dev/sdb1 /dev/sdc1
Logical volume mirror converted.
lvs command to verify that the mirror is restored.
[root@link-08 ~]# lvs -a -o +devices
LV VG Attr LSize Origin Snap% Move Log Copy% Devices
groupfs vg mwi-a- 752.00M groupfs_mlog 68.62 groupfs_mimage_0(0),groupfs_mimage_1(0)
[groupfs_mimage_0] vg iwi-ao 752.00M /dev/sdb1(0)
[groupfs_mimage_1] vg iwi-ao 752.00M /dev/sda1(0)
[groupfs_mlog] vg lwi-ao 4.00M /dev/sdc1(0)
[root@link-07 backup]# lvs -a -o +devices
Couldn't find device with uuid 'FmGRh3-zhok-iVI8-7qTD-S5BI-MAEN-NYM5Sk'.
Couldn't find all physical volumes for volume group VG.
Couldn't find device with uuid 'FmGRh3-zhok-iVI8-7qTD-S5BI-MAEN-NYM5Sk'.
Couldn't find all physical volumes for volume group VG.
...
/etc/lvm/archive directory. Look in the file VolumeGroupName_xxxx.vg for the last known valid archived LVM metadata for that volume group.
partial (-P) argument will enable you to find the UUID of the missing corrupted physical volume.
[root@link-07 backup]# vgchange -an --partial
Partial mode. Incomplete volume groups will be activated read-only.
Couldn't find device with uuid 'FmGRh3-zhok-iVI8-7qTD-S5BI-MAEN-NYM5Sk'.
Couldn't find device with uuid 'FmGRh3-zhok-iVI8-7qTD-S5BI-MAEN-NYM5Sk'.
...
--uuid and --restorefile arguments of the pvcreate command to restore the physical volume. The following example labels the /dev/sdh1 device as a physical volume with the UUID indicated above, FmGRh3-zhok-iVI8-7qTD-S5BI-MAEN-NYM5Sk. This command restores the physical volume label with the metadata information contained in VG_00050.vg, the most recent good archived metadata for the volume group. The restorefile argument instructs the pvcreate
command to make the new physical volume compatible with the old one on
the volume group, ensuring that the new metadata will not be placed
where the old physical volume contained data (which could happen, for
example, if the original pvcreate command
had used the command line arguments that control metadata placement, or
if the physical volume was originally created using a different version
of the software that used different defaults). The pvcreate command overwrites only the LVM metadata areas and does not affect the existing data areas.
[root@link-07 backup]# pvcreate --uuid "FmGRh3-zhok-iVI8-7qTD-S5BI-MAEN-NYM5Sk" --restorefile /etc/lvm/archive/VG_00050.vg /dev/sdh1
Physical volume "/dev/sdh1" successfully created
vgcfgrestore command to restore the volume group's metadata.
[root@link-07 backup]# vgcfgrestore VG
Restored volume group VG
[root@link-07 backup]# lvs -a -o +devices
LV VG Attr LSize Origin Snap% Move Log Copy% Devices
stripe VG -wi--- 300.00G /dev/sdh1 (0),/dev/sda1(0)
stripe VG -wi--- 300.00G /dev/sdh1 (34728),/dev/sdb1(0)
[root@link-07 backup]#lvchange -ay /dev/VG/stripe[root@link-07 backup]#lvs -a -o +devicesLV VG Attr LSize Origin Snap% Move Log Copy% Devices stripe VG -wi-a- 300.00G /dev/sdh1 (0),/dev/sda1(0) stripe VG -wi-a- 300.00G /dev/sdh1 (34728),/dev/sdb1(0)
fsck command to recover that data.
--partial and --verbose arguments of the vgdisplay
command to display the UUIDs and sizes of any physical volumes that are
no longer present. If you wish to substitute another physical volume of
the same size, you can use the pvcreate command with the --restorefile and --uuid arguments to initialize a new device with the same UUID as the missing physical volume. You can then use the vgcfgrestore command to restore the volume group's metadata.
--partial argument of the vgchange command. You can remove all the logical volumes that used that physical volume from the volume group with the --removemissing argument of the vgreduce command.
vgreduce command with the --test argument to verify what you will be destroying.
vgreduce command is reversible in a sense if you immediately use the vgcfgrestore command to restore the volume group metadata to its previous state. For example, if you used the --removemissing argument of the vgreduce command without the --test
argument and find you have removed logical volumes you wanted to keep,
you can still replace the physical volume and use another vgcfgrestore command to return the volume group to its previous state.
vgdisplay or vgs
commands. This is because these commands round figures to 2 decimal
places to provide human-readable output. To specify exact size, use free
physical extent count instead of some multiple of bytes to determine
the size of the logical volume.
vgdisplay command, by default, includes this line of output that indicates the free physical extents.
# vgdisplay
--- Volume group ---
...
Free PE / Size 8780 / 34.30 GB
vg_free_count and vg_extent_count arguments of the vgs command to display the free extents and the total number of extents.
[root@tng3-1 ~]# vgs -o +vg_free_count,vg_extent_count
VG #PV #LV #SN Attr VSize VFree Free #Ext
testvg 2 0 0 wz--n- 34.30G 34.30G 8780 8780
# lvcreate -l8780 -n testlv testvg# vgs -o +vg_free_count,vg_extent_count
VG #PV #LV #SN Attr VSize VFree Free #Ext
testvg 2 1 0 wz--n- 34.30G 0 0 8780
-l argument of the lvcreate command. For information, see Section 4.4.1, “Creating Linear Logical Volumes”.
system-config-lvm. The LVM chapter of the Storage Administration Guide provides step-by-step instructions for configuring an LVM logical volume using this utility.
dmraid command use the Device Mapper. The application interface to the Device Mapper is the ioctl system call. The user interface is the dmsetup command.
dmsetup command. For information about the format of devices in a mapping table, see Section A.1, “Device Table Mappings”. For information about using the dmsetup command to query a device, see Section A.2, “The dmsetup Command”.
start length mapping[mapping_parameters...]
start parameter must equal 0. The start + length parameters on one line must equal the start on the next line. Which mapping parameters are specified in a line of the mapping table depends on which mapping type is specified on the line.
/dev/hda) or by the major and minor numbers in the format major:minor. The major:minor format is preferred because it avoids pathname lookups.
0 35258368 linear 8:48 65920 35258368 35258368 linear 8:32 65920 70516736 17694720 linear 8:16 17694976 88211456 17694720 linear 8:16 256
linear. The rest of the line consists of the parameters for a linear target.
start lengthlineardevice offset
startlengthdevicemajor:minor
offset0 16384000 linear 8:2 41156992
/dev/hda.
0 20971520 linear /dev/hda 384
start lengthstriped#stripes chunk_size device1 offset1 ... deviceN offsetN
device and offset parameters for each stripe.
startlength#stripeschunk_sizedevicemajor:minor.
offset0 73728 striped 3 128 8:9 384 8:8 384 8:7 9789824
0 65536 striped 2 512 /dev/hda 0 /dev/hdb 0
start lengthmirrorlog_type #logargs logarg1 ... logargN #devs device1 offset1 ... deviceN offsetN
startlengthlog_typecoreregionsize [[no]sync] [block_on_error]
disklogdevice regionsize [[no]sync] [block_on_error]
clustered_coreregionsize UUID [[no]sync] [block_on_error]
clustered_disklogdevice regionsize UUID [[no]sync] [block_on_error]
regionsize argument specifies the size of these regions.
UUID
argument is a unique identifier associated with the mirror log device
so that the log state can be maintained throughout the cluster.
[no]sync argument can be used to specify the mirror as "in-sync" or "out-of-sync". The block_on_error argument is used to tell the mirror to respond to errors rather than ignoring them.
#log_argslogargs#log-args parameter and the valid log arguments are determined by the log_type parameter.
#devsdevicemajor:minor. A block device and offset is specified for each mirror leg, as indicated by the #devs parameter.
offset#devs parameter.
0 52428800 mirror clustered_disk 4 253:2 1024 UUID block_on_error 3 253:3 0 253:4 0 253:5 0
UUIDblock_on_errorlinear mapping containing the original mapping table of the source volume.
linear mapping used
as the copy-on-write (COW) device for the source volume; for each write,
the original data is saved in the COW device of each snapshot to keep
its visible content unchanged (until the COW device fills up).
snapshot mapping combining #1 and #2, which is the visible snapshot volume
base and a snapshot volume named snap based on that volume.
#lvcreate -L 1G -n base volumeGroup#lvcreate -L 100M --snapshot -n snap volumeGroup/base
#dmsetup table|grep volumeGroupvolumeGroup-base-real: 0 2097152 linear 8:19 384 volumeGroup-snap-cow: 0 204800 linear 8:19 2097536 volumeGroup-snap: 0 2097152 snapshot 254:11 254:12 P 16 volumeGroup-base: 0 2097152 snapshot-origin 254:11 #ls -lL /dev/mapper/volumeGroup-*brw------- 1 root root 254, 11 29 ago 18:15 /dev/mapper/volumeGroup-base-real brw------- 1 root root 254, 12 29 ago 18:15 /dev/mapper/volumeGroup-snap-cow brw------- 1 root root 254, 13 29 ago 18:15 /dev/mapper/volumeGroup-snap brw------- 1 root root 254, 10 29 ago 18:14 /dev/mapper/volumeGroup-base
snapshot-origin target is as follows:
start lengthsnapshot-originorigin
startlengthoriginsnapshot-origin will normally have
one or more snapshots based on it. Reads will be mapped directly to the
backing device. For each write, the original data will be saved in the
COW device of each snapshot to keep its visible content unchanged until
the COW device fills up.
snapshot target is as follows:
start lengthsnapshotorigin COW-deviceP|Nchunksize
startlengthoriginCOW-devicechunksizesnapshot-origin target with an origin device of 254:11.
0 2097152 snapshot-origin 254:11
snapshot
target with an origin device of 254:11 and a COW device of 254:12. This
snapshot device is persistent across reboots and the chunk size for the
data stored on the COW device is 16 sectors.
0 2097152 snapshot 254:11 254:12 P 16
error mapping target takes no additional parameters besides the start and length parameters.
error target.
0 65536 error
zero mapping target is a block device equivalent of /dev/zero.
A read operation to this mapping returns blocks of zeros. Data written
to this mapping is discarded, but the write succeeds. The zero mapping target takes no additional parameters besides the start and length parameters.
zero target for a 16Tb Device.
0 65536 zero
multipath target is as follows:
start lengthmultipath#features [feature1 ... featureN] #handlerargs [handlerarg1 ... handlerargN] #pathgroups pathgroup pathgroupargs1 ... pathgroupargsN
pathgroupargs parameters for each path group.
startlength#featuresfeature parameter and the next device mapping parameter is #handlerargs. Currently there is one supported multipath feature, queue_if_no_path. This indicates that this multipathed device is currently set to queue I/O operations if there is no path available.
no_path_retry option in the multipath.conf
file has been set to queue I/O operations only until all paths have
been marked as failed after a set number of attempts have been made to
use the paths, the mapping would appear as follows until all the path
checkers have failed the specified number of checks.
0 71014400 multipath 1 queue_if_no_path 0 2 1 round-robin 0 2 1 66:128 \ 1000 65:64 1000 round-robin 0 2 1 8:0 1000 67:192 1000
0 71014400 multipath 0 0 2 1 round-robin 0 2 1 66:128 1000 65:64 1000 \ round-robin 0 2 1 8:0 1000 67:192 1000
#handlerargs#pathgroups.
#pathgroupspathgroupargs parameters for each path group.
pathgrouppathgroupsargspathselector #selectorargs #paths #pathargs device1 ioreqs1 ... deviceN ioreqsN pathselector#selectorargs#paths#pathargsioreqs argument.
devicemajor:minor
ioreqs
0 71014400 multipath 0 0 4 1 round-robin 0 1 1 66:112 1000 \ round-robin 0 1 1 67:176 1000 round-robin 0 1 1 68:240 1000 \ round-robin 0 1 1 65:48 1000
0 71014400 multipath 0 0 1 1 round-robin 0 4 1 66:112 1000 \ 67:176 1000 68:240 1000 65:48 1000
crypt target encrypts the data passing through the specified device. It uses the kernel Crypto API.
crypt target is as follows:
start lengthcryptcipher key IV-offset device offset
startlengthciphercipher[-chainmode]-ivmode[:iv options].
cipher/proc/crypto (for example, aes).
chainmodecbc. Do not use ebc; it does not use an initial vector (IV).
ivmode[:iv options]plain or essiv:hash. An ivmode of -plain uses the sector number (plus IV offset) as the IV. An ivmode of -essiv is an enhancement avoiding a watermark weakness
keyIV-offsetdevicemajor:minor
offsetcrypt target.
0 2097152 crypt aes-plain 0123456789abcdef0123456789abcdef 0 /dev/hda 0
dmsetup command is a command line
wrapper for communication with the Device Mapper. For general system
information about LVM devices, you may find the info, ls, status, and deps options of the dmsetup command to be useful, as described in the following subsections.
dmsetup command, see the dmsetup(8) man page.
dmsetup info device
command provides summary information about Device Mapper devices. If
you do not specify a device name, the output is information about all of
the currently configured Device Mapper devices. If you specify a
device, then this command yields information for that device only.
dmsetup info command provides information in the following categories:
NameStateSUSPENDED, ACTIVE, and READ-ONLY. The dmsetup suspend command sets a device state to SUSPENDED. When a device is suspended, all I/O operations to that device stop. The dmsetup resume command restores a device state to ACTIVE.
Read Ahead--readahead option of the dmsetup command.
Tables presentLIVE and INACTIVE. An INACTIVE state indicates that a table has been loaded which will be swapped in when a dmsetup resume command restores a device state to ACTIVE, at which point the table's state becomes LIVE. For information, see the dmsetup man page.
Open countmount command opens a device.
Event numberdmsetup wait n command allows the user to wait for the n'th event, blocking the call until it is received.
Major, minorNumber of targetsUUIDdmsetup info command.
[root@ask-07 ~]# dmsetup info
Name: testgfsvg-testgfslv1
State: ACTIVE
Read Ahead: 256
Tables present: LIVE
Open count: 0
Event number: 0
Major, minor: 253, 2
Number of targets: 2
UUID: LVM-K528WUGQgPadNXYcFrrf9LnPlUMswgkCkpgPIgYzSvigM7SfeWCypddNSWtNzc2N
...
Name: VolGroup00-LogVol00
State: ACTIVE
Read Ahead: 256
Tables present: LIVE
Open count: 1
Event number: 0
Major, minor: 253, 0
Number of targets: 1
UUID: LVM-tOcS1kqFV9drb0X1Vr8sxeYP0tqcrpdegyqj5lZxe45JMGlmvtqLmbLpBcenh2L3
dmsetup ls command. You can list devices that have at least one target of a specified type with the dmsetup ls --target target_type command. For other options of the dmsetup ls, see the dmsetup man page.
[root@ask-07 ~]# dmsetup ls
testgfsvg-testgfslv3 (253, 4)
testgfsvg-testgfslv2 (253, 3)
testgfsvg-testgfslv1 (253, 2)
VolGroup00-LogVol01 (253, 1)
VolGroup00-LogVol00 (253, 0)
[root@grant-01 ~]# dmsetup ls --target mirror
lock_stress-grant--02.1722 (253, 34)
lock_stress-grant--01.1720 (253, 18)
lock_stress-grant--03.1718 (253, 52)
lock_stress-grant--02.1716 (253, 40)
lock_stress-grant--03.1713 (253, 47)
lock_stress-grant--02.1709 (253, 23)
lock_stress-grant--01.1707 (253, 8)
lock_stress-grant--01.1724 (253, 14)
lock_stress-grant--03.1711 (253, 27)
dmsetup status device
command provides status information for each target in a specified
device. If you do not specify a device name, the output is information
about all of the currently configured Device Mapper devices. You can
list the status only of devices that have at least one target of a
specified type with the dmsetup status --target target_type command.
[root@ask-07 ~]# dmsetup status
testgfsvg-testgfslv3: 0 312352768 linear
testgfsvg-testgfslv2: 0 312352768 linear
testgfsvg-testgfslv1: 0 312352768 linear
testgfsvg-testgfslv1: 312352768 50331648 linear
VolGroup00-LogVol01: 0 4063232 linear
VolGroup00-LogVol00: 0 151912448 linear
dmsetup deps device
command provides a list of (major, minor) pairs for devices referenced
by the mapping table for the specified device. If you do not specify a
device name, the output is information about all of the currently
configured Device Mapper devices.
[root@ask-07 ~]# dmsetup deps
testgfsvg-testgfslv3: 1 dependencies : (8, 16)
testgfsvg-testgfslv2: 1 dependencies : (8, 16)
testgfsvg-testgfslv1: 1 dependencies : (8, 16)
VolGroup00-LogVol01: 1 dependencies : (8, 2)
VolGroup00-LogVol00: 1 dependencies : (8, 2)
lock_stress-grant--02.1722:
[root@grant-01 ~]# dmsetup deps lock_stress-grant--02.1722
3 dependencies : (253, 33) (253, 32) (253, 31)
udev device manager is to provide a dynamic way of setting up nodes in the /dev directory. The creation of these nodes is directed by the application of udev rules in userspace. These rules are processed on udev
events sent from the kernel directly as a result of adding, removing or
changing particular devices. This provides a convenient and central
mechanism for hotplugging support.
udev
device manager is able to create any symbolic links with their own
names as well, providing users the freedom to choose their own
customized naming and directory structure in the/dev directory, if needed.
udev event contains basic
information about the device being processed, such as its name, the
subsystem it belongs to, the device's type, its major and minor number
used, and the type of the event. Given that, and having the possibility
of accessing all the information found in the /sys directory that is also accessible within udev
rules, the users are able to utilize simple filters based on this
information and run the rules conditionally based on this information.
udev device manager also provides a
centralized way of setting up the nodes' permissions. A user can easily
add a customized set of rules to define the permissions for any device
specified by any bit of information that is available while processing
the event.
udev rules directly. The udev
device manager can call these programs to provide further processing
that is needed to handle the event. Also, the program can export
environment variables as a result of this processing. Any results given
can be used further in the rules as a supplementary source of
information.
udev library is able to receive and process udev events with all the information that is available, so the processing is not bound to the udev daemon only.
udev integration. This synchronizes the Device Mapper with all udev
processing related to Device Mapper devices, including LVM devices. The
synchronization is needed since the rule application in the udev daemon is a form of parallel processing with the program that is the source of the device's changes (such as dmsetup
and LVM). Without this support, it was a common problem for a user to
try to remove a device that was still open and processed by udev
rules as a result of a previous change event; this was particularly
common when there was a very short time between changes for that device.
udev rules for Device Mapper devices in general and for LVM as well. Table A.1, “udev Rules for Device-Mapper Devices” summarizes these rules, which are installed in /lib/udev/rules.d.
| Filename | Description | ||
|---|---|---|---|
10-dm.rules
|
| ||
11-dm-lvm.rules
|
| ||
13-dm-disk.rules
|
Contains rules to be applied for all Device Mapper devices in general and creates symlinks in the /dev/disk/by-id, /dev/disk/by-uuid and the /dev/disk/by-uuid directories.
| ||
95-dm-notify.rules
|
Contains the rule to notify the waiting process using libdevmapper (just like LVM and dmsetup). The notification is done after all previous rules are applied, to ensure any udev processing is complete. Notified process is then resumed.
|
12-dm-permissions.rules file. This file is not installed in the /lib/udev/rules directory; it is found in the /usr/share/doc/device-mapper-version directory. The 12-dm-permissions.rules
file is a template containing hints for how to set the permissions,
based on some matching rules given as an example; the file contains
examples for some common situations. You can edit this file and place it
manually in the /etc/udev/rules.d directory where it will survive updates, so the settings will remain.
DM_NAME: Device Mapper device name
DM_UUID: Device Mapper device UUID
DM_SUSPENDED: the suspended state of Device Mapper device
DM_UDEV_RULES_VSN: udev
rules version (this is primarily for all other rules to check that
previously mentioned variables are set directly by official Device
Mapper rules)
11-dm-lvm.rules:
DM_LV_NAME: logical volume name
DM_VG_NAME: volume group name
DM_LV_LAYER: LVM layer name
12-dm-permissions.rules file to define a permission for specific Device Mapper devices, as documented in the 12-dm-permissions.rules file.
dmsetup commands that support udev integration.
| Command | Description |
|---|---|
dmsetup udevcomplete
|
Used to notify that udev has completed processing the rules and unlocks waiting process (called from within udev rules in 95-dm-notify.rules)
|
dmsetup udevcomplete_all
| Used for debugging purposes to manually unlock all waiting processes |
dmsetup udevcookies
| Used for debugging purposes, to show all existing cookies (system-wide semaphores) |
dmsetup udevcreatecookie
| Used to create a cookie (semaphore) manually. This is useful to run more processes under one synchronization resource. |
dmsetup udevreleasecookie
|
Used to wait for all udev processing related to all processes put under that one synchronization cookie.
|
dmsetup options that support udev integration are as follows.
--udevcookieudevcreatecookie and udevreleasecookie:
COOKIE=$(dmsetup udevcreatecookie) dmsetupcommand--udevcookie $COOKIE .... dmsetupcommand--udevcookie $COOKIE .... .... dmsetupcommand--udevcookie $COOKIE .... dmsetup udevreleasecookie --udevcookie $COOKIE
--udevcookie option, you can just export the variable into an environment of the process:
export DM_UDEV_COOKIE=$(dmsetup udevcreatecookie) dmsetupcommand... dmsetupcommand... ... dmsetupcommand...
--noudevruleslibdevmapper itself (the old way). This option is for debugging purposes, if udev does not work correctly.
--noudevsyncudev synchronization. This is also for debugging purposes.
dmsetup and its options, see the dmsetup(8) man page.
udev integration:
--noudevrules: as for the dmsetup command, disables udev rules.
--noudevsync: as for the dmsetup command, disables udev synchronization.
lvm.conf file includes the following options that support udev integration:
udev_rules: enables/disables udev_rules for all LVM2 commands globally
udev_sync: enables/disables udev synchronization for all LVM commands globally
lvm.conf file options, see the inline comments in the lvm.conf file.
lvm.conf configuration file is loaded from the directory specified by the environment variable LVM_SYSTEM_DIR, which is set to /etc/lvm by default.
lvm.conf file can specify additional
configuration files to load. Settings in later files override settings
from earlier ones. To display the settings in use after loading all the
configuration files, execute the lvm dumpconfig command.
hosttag.conflvm_hosttag.conf.
If that file defines new tags, then further configuration files will be
appended to the list of tiles to read in. For information on host tags,
see Section C.2, “Host Tags”.
lvm.conf configuration file. Your configuration file may differ slightly from this one.
# This is an example configuration file for the LVM2 system.
# It contains the default settings that would be used if there was no
# /etc/lvm/lvm.conf file.
#
# Refer to 'man lvm.conf' for further information including the file layout.
#
# To put this file in a different directory and override /etc/lvm set
# the environment variable LVM_SYSTEM_DIR before running the tools.
# This section allows you to configure which block devices should
# be used by the LVM system.
devices {
# Where do you want your volume groups to appear ?
dir = "/dev"
# An array of directories that contain the device nodes you wish
# to use with LVM2.
scan = [ "/dev" ]
# If several entries in the scanned directories correspond to the
# same block device and the tools need to display a name for device,
# all the pathnames are matched against each item in the following
# list of regular expressions in turn and the first match is used.
# preferred_names = [ ]
# Try to avoid using undescriptive /dev/dm-N names, if present.
preferred_names = [ "^/dev/mpath/", "^/dev/mapper/mpath", "^/dev/[hs]d" ]
# A filter that tells LVM2 to only use a restricted set of devices.
# The filter consists of an array of regular expressions. These
# expressions can be delimited by a character of your choice, and
# prefixed with either an 'a' (for accept) or 'r' (for reject).
# The first expression found to match a device name determines if
# the device will be accepted or rejected (ignored). Devices that
# don't match any patterns are accepted.
# Be careful if there there are symbolic links or multiple filesystem
# entries for the same device as each name is checked separately against
# the list of patterns. The effect is that if any name matches any 'a'
# pattern, the device is accepted; otherwise if any name matches any 'r'
# pattern it is rejected; otherwise it is accepted.
# Don't have more than one filter line active at once: only one gets used.
# Run vgscan after you change this parameter to ensure that
# the cache file gets regenerated (see below).
# If it doesn't do what you expect, check the output of 'vgscan -vvvv'.
# By default we accept every block device:
filter = [ "a/.*/" ]
# Exclude the cdrom drive
# filter = [ "r|/dev/cdrom|" ]
# When testing I like to work with just loopback devices:
# filter = [ "a/loop/", "r/.*/" ]
# Or maybe all loops and ide drives except hdc:
# filter =[ "a|loop|", "r|/dev/hdc|", "a|/dev/ide|", "r|.*|" ]
# Use anchors if you want to be really specific
# filter = [ "a|^/dev/hda8$|", "r/.*/" ]
# The results of the filtering are cached on disk to avoid
# rescanning dud devices (which can take a very long time).
# By default this cache is stored in the /etc/lvm/cache directory
# in a file called '.cache'.
# It is safe to delete the contents: the tools regenerate it.
# (The old setting 'cache' is still respected if neither of
# these new ones is present.)
cache_dir = "/etc/lvm/cache"
cache_file_prefix = ""
# You can turn off writing this cache file by setting this to 0.
write_cache_state = 1
# Advanced settings.
# List of pairs of additional acceptable block device types found
# in /proc/devices with maximum (non-zero) number of partitions.
# types = [ "fd", 16 ]
# If sysfs is mounted (2.6 kernels) restrict device scanning to
# the block devices it believes are valid.
# 1 enables; 0 disables.
sysfs_scan = 1
# By default, LVM2 will ignore devices used as components of
# software RAID (md) devices by looking for md superblocks.
# 1 enables; 0 disables.
md_component_detection = 1
# By default, if a PV is placed directly upon an md device, LVM2
# will align its data blocks with the md device's stripe-width.
# 1 enables; 0 disables.
md_chunk_alignment = 1
# By default, the start of a PV's data area will be a multiple of
# the 'minimum_io_size' or 'optimal_io_size' exposed in sysfs.
# - minimum_io_size - the smallest request the device can perform
# w/o incurring a read-modify-write penalty (e.g. MD's chunk size)
# - optimal_io_size - the device's preferred unit of receiving I/O
# (e.g. MD's stripe width)
# minimum_io_size is used if optimal_io_size is undefined (0).
# If md_chunk_alignment is enabled, that detects the optimal_io_size.
# This setting takes precedence over md_chunk_alignment.
# 1 enables; 0 disables.
data_alignment_detection = 1
# Alignment (in KB) of start of data area when creating a new PV.
# If a PV is placed directly upon an md device and md_chunk_alignment or
# data_alignment_detection is enabled this parameter is ignored.
# Set to 0 for the default alignment of 64KB or page size, if larger.
data_alignment = 0
# By default, the start of the PV's aligned data area will be shifted by
# the 'alignment_offset' exposed in sysfs. This offset is often 0 but
# may be non-zero; e.g.: certain 4KB sector drives that compensate for
# windows partitioning will have an alignment_offset of 3584 bytes
# (sector 7 is the lowest aligned logical block, the 4KB sectors start
# at LBA -1, and consequently sector 63 is aligned on a 4KB boundary).
# 1 enables; 0 disables.
data_alignment_offset_detection = 1
# If, while scanning the system for PVs, LVM2 encounters a device-mapper
# device that has its I/O suspended, it waits for it to become accessible.
# Set this to 1 to skip such devices. This should only be needed
# in recovery situations.
ignore_suspended_devices = 0
}
# This section that allows you to configure the nature of the
# information that LVM2 reports.
log {
# Controls the messages sent to stdout or stderr.
# There are three levels of verbosity, 3 being the most verbose.
verbose = 0
# Should we send log messages through syslog?
# 1 is yes; 0 is no.
syslog = 1
# Should we log error and debug messages to a file?
# By default there is no log file.
#file = "/var/log/lvm2.log"
# Should we overwrite the log file each time the program is run?
# By default we append.
overwrite = 0
# What level of log messages should we send to the log file and/or syslog?
# There are 6 syslog-like log levels currently in use - 2 to 7 inclusive.
# 7 is the most verbose (LOG_DEBUG).
level = 0
# Format of output messages
# Whether or not (1 or 0) to indent messages according to their severity
indent = 1
# Whether or not (1 or 0) to display the command name on each line output
command_names = 0
# A prefix to use before the message text (but after the command name,
# if selected). Default is two spaces, so you can see/grep the severity
# of each message.
prefix = " "
# To make the messages look similar to the original LVM tools use:
# indent = 0
# command_names = 1
# prefix = " -- "
# Set this if you want log messages during activation.
# Don't use this in low memory situations (can deadlock).
# activation = 0
}
# Configuration of metadata backups and archiving. In LVM2 when we
# talk about a 'backup' we mean making a copy of the metadata for the
# *current* system. The 'archive' contains old metadata configurations.
# Backups are stored in a human readeable text format.
backup {
# Should we maintain a backup of the current metadata configuration ?
# Use 1 for Yes; 0 for No.
# Think very hard before turning this off!
backup = 1
# Where shall we keep it ?
# Remember to back up this directory regularly!
backup_dir = "/etc/lvm/backup"
# Should we maintain an archive of old metadata configurations.
# Use 1 for Yes; 0 for No.
# On by default. Think very hard before turning this off.
archive = 1
# Where should archived files go ?
# Remember to back up this directory regularly!
archive_dir = "/etc/lvm/archive"
# What is the minimum number of archive files you wish to keep ?
retain_min = 10
# What is the minimum time you wish to keep an archive file for ?
retain_days = 30
}
# Settings for the running LVM2 in shell (readline) mode.
shell {
# Number of lines of history to store in ~/.lvm_history
history_size = 100
}
# Miscellaneous global LVM2 settings
global {
library_dir = "/lib64"
# The file creation mask for any files and directories created.
# Interpreted as octal if the first digit is zero.
umask = 077
# Allow other users to read the files
#umask = 022
# Enabling test mode means that no changes to the on disk metadata
# will be made. Equivalent to having the -t option on every
# command. Defaults to off.
test = 0
# Default value for --units argument
units = "h"
# Since version 2.02.54, the tools distinguish between powers of
# 1024 bytes (e.g. KiB, MiB, GiB) and powers of 1000 bytes (e.g.
# KB, MB, GB).
# If you have scripts that depend on the old behaviour, set this to 0
# temporarily until you update them.
si_unit_consistency = 1
# Whether or not to communicate with the kernel device-mapper.
# Set to 0 if you want to use the tools to manipulate LVM metadata
# without activating any logical volumes.
# If the device-mapper kernel driver is not present in your kernel
# setting this to 0 should suppress the error messages.
activation = 1
# If we can't communicate with device-mapper, should we try running
# the LVM1 tools?
# This option only applies to 2.4 kernels and is provided to help you
# switch between device-mapper kernels and LVM1 kernels.
# The LVM1 tools need to be installed with .lvm1 suffices
# e.g. vgscan.lvm1 and they will stop working after you start using
# the new lvm2 on-disk metadata format.
# The default value is set when the tools are built.
# fallback_to_lvm1 = 0
# The default metadata format that commands should use - "lvm1" or "lvm2".
# The command line override is -M1 or -M2.
# Defaults to "lvm2".
# format = "lvm2"
# Location of proc filesystem
proc = "/proc"
# Type of locking to use. Defaults to local file-based locking (1).
# Turn locking off by setting to 0 (dangerous: risks metadata corruption
# if LVM2 commands get run concurrently).
# Type 2 uses the external shared library locking_library.
# Type 3 uses built-in clustered locking.
# Type 4 uses read-only locking which forbids any operations that might
# change metadata.
locking_type = 3
# Set to 0 to fail when a lock request cannot be satisfied immediately.
wait_for_locks = 1
# If using external locking (type 2) and initialisation fails,
# with this set to 1 an attempt will be made to use the built-in
# clustered locking.
# If you are using a customised locking_library you should set this to 0.
fallback_to_clustered_locking = 1
# If an attempt to initialise type 2 or type 3 locking failed, perhaps
# because cluster components such as clvmd are not running, with this set
# to 1 an attempt will be made to use local file-based locking (type 1).
# If this succeeds, only commands against local volume groups will proceed.
# Volume Groups marked as clustered will be ignored.
fallback_to_local_locking = 1
# Local non-LV directory that holds file-based locks while commands are
# in progress. A directory like /tmp that may get wiped on reboot is OK.
locking_dir = "/var/lock/lvm"
# Whenever there are competing read-only and read-write access requests for
# a volume group's metadata, instead of always granting the read-only
# requests immediately, delay them to allow the read-write requests to be
# serviced. Without this setting, write access may be stalled by a high
# volume of read-only requests.
# NB. This option only affects locking_type = 1 viz. local file-based
# locking.
prioritise_write_locks = 1
# Other entries can go here to allow you to load shared libraries
# e.g. if support for LVM1 metadata was compiled as a shared library use
# format_libraries = "liblvm2format1.so"
# Full pathnames can be given.
# Search this directory first for shared libraries.
# library_dir = "/lib"
# The external locking library to load if locking_type is set to 2.
# locking_library = "liblvm2clusterlock.so"
# Treat any internal errors as fatal errors, aborting the process that
# encountered the internal error. Please only enable for debugging.
abort_on_internal_errors = 0
}
activation {
# Set to 0 to disable udev synchronisation (if compiled into the binaries).
# Processes will not wait for notification from udev.
# They will continue irrespective of any possible udev processing
# in the background. You should only use this if udev is not running
# or has rules that ignore the devices LVM2 creates.
# The command line argument --nodevsync takes precedence over this setting.
# If set to 1 when udev is not running, and there are LVM2 processes
# waiting for udev, run 'dmsetup udevcomplete_all' manually to wake them up.
udev_sync = 1
# Set to 0 to disable the udev rules installed by LVM2 (if built with
# --enable-udev_rules). LVM2 will then manage the /dev nodes and symlinks
# for active logical volumes directly itself.
# N.B. Manual intervention may be required if this setting is changed
# while any logical volumes are active.
udev_rules = 1
# How to fill in missing stripes if activating an incomplete volume.
# Using "error" will make inaccessible parts of the device return
# I/O errors on access. You can instead use a device path, in which
# case, that device will be used to in place of missing stripes.
# But note that using anything other than "error" with mirrored
# or snapshotted volumes is likely to result in data corruption.
missing_stripe_filler = "error"
# How much stack (in KB) to reserve for use while devices suspended
reserved_stack = 256
# How much memory (in KB) to reserve for use while devices suspended
reserved_memory = 8192
# Nice value used while devices suspended
process_priority = -18
# If volume_list is defined, each LV is only activated if there is a
# match against the list.
# "vgname" and "vgname/lvname" are matched exactly.
# "@tag" matches any tag set in the LV or VG.
# "@*" matches if any tag defined on the host is also set in the LV or VG
#
# volume_list = [ "vg1", "vg2/lvol1", "@tag1", "@*" ]
# Size (in KB) of each copy operation when mirroring
mirror_region_size = 512
# Setting to use when there is no readahead value stored in the metadata.
#
# "none" - Disable readahead.
# "auto" - Use default value chosen by kernel.
readahead = "auto"
# 'mirror_image_fault_policy' and 'mirror_log_fault_policy' define
# how a device failure affecting a mirror is handled.
# A mirror is composed of mirror images (copies) and a log.
# A disk log ensures that a mirror does not need to be re-synced
# (all copies made the same) every time a machine reboots or crashes.
#
# In the event of a failure, the specified policy will be used to determine
# what happens. This applies to automatic repairs (when the mirror is being
# monitored by dmeventd) and to manual lvconvert --repair when
# --use-policies is given.
#
# "remove" - Simply remove the faulty device and run without it. If
# the log device fails, the mirror would convert to using
# an in-memory log. This means the mirror will not
# remember its sync status across crashes/reboots and
# the entire mirror will be re-synced. If a
# mirror image fails, the mirror will convert to a
# non-mirrored device if there is only one remaining good
# copy.
#
# "allocate" - Remove the faulty device and try to allocate space on
# a new device to be a replacement for the failed device.
# Using this policy for the log is fast and maintains the
# ability to remember sync state through crashes/reboots.
# Using this policy for a mirror device is slow, as it
# requires the mirror to resynchronize the devices, but it
# will preserve the mirror characteristic of the device.
# This policy acts like "remove" if no suitable device and
# space can be allocated for the replacement.
#
# "allocate_anywhere" - Not yet implemented. Useful to place the log device
# temporarily on same physical volume as one of the mirror
# images. This policy is not recommended for mirror devices
# since it would break the redundant nature of the mirror. This
# policy acts like "remove" if no suitable device and space can
# be allocated for the replacement.
mirror_log_fault_policy = "allocate"
mirror_image_fault_policy = "remove"
}
####################
# Advanced section #
####################
# Metadata settings
#
# metadata {
# Default number of copies of metadata to hold on each PV. 0, 1 or 2.
# You might want to override it from the command line with 0
# when running pvcreate on new PVs which are to be added to large VGs.
# pvmetadatacopies = 1
# Approximate default size of on-disk metadata areas in sectors.
# You should increase this if you have large volume groups or
# you want to retain a large on-disk history of your metadata changes.
# pvmetadatasize = 255
# List of directories holding live copies of text format metadata.
# These directories must not be on logical volumes!
# It's possible to use LVM2 with a couple of directories here,
# preferably on different (non-LV) filesystems, and with no other
# on-disk metadata (pvmetadatacopies = 0). Or this can be in
# addition to on-disk metadata areas.
# The feature was originally added to simplify testing and is not
# supported under low memory situations - the machine could lock up.
#
# Never edit any files in these directories by hand unless you
# you are absolutely sure you know what you are doing! Use
# the supplied toolset to make changes (e.g. vgcfgrestore).
# dirs = [ "/etc/lvm/metadata", "/mnt/disk2/lvm/metadata2" ]
#}
# Event daemon
#
dmeventd {
# mirror_library is the library used when monitoring a mirror device.
#
# "libdevmapper-event-lvm2mirror.so" attempts to recover from
# failures. It removes failed devices from a volume group and
# reconfigures a mirror as necessary. If no mirror library is
# provided, mirrors are not monitored through dmeventd.
mirror_library = "libdevmapper-event-lvm2mirror.so"
# snapshot_library is the library used when monitoring a snapshot device.
#
# "libdevmapper-event-lvm2snapshot.so" monitors the filling of
# snapshots and emits a warning through syslog, when the use of
# snapshot exceedes 80%. The warning is repeated when 85%, 90% and
# 95% of the snapshot are filled.
snapshot_library = "libdevmapper-event-lvm2snapshot.so"
}
database tag.
lvs @database
--addtag or --deltag option of the pvchange command.
--addtag or --deltag option of the vgchange or vgcreate commands.
--addtag or --deltag option of the lvchange or lvcreate commands.
hosttags = 1 in the tags
section, a host tag is automatically defined using the machine's
hostname. This allow you to use a common configuration file which can be
replicated on all your machines so they hold identical copies of the
file, but the behavior can differ between machines according to the
hostname.
hosttag.conf. If that file defines new tags, then further configuration files will be appended to the list of files to read in.
tag1, and defines tag2 if the hostname is host1.
tags { tag1 { } tag2 { host_list = ["host1"] } }
vgchange -ay) and only activates vg1/lvol0 and any logical volumes or volume groups with the database tag in the metadata on that host.
activation { volume_list = ["vg1/lvol0", "@database" ] }
tags { hosttags = 1 }
vg1/lvol2 only on host db2, do the following:
lvchange --addtag @db2 vg1/lvol2 from any host in the cluster.
lvchange -ay vg1/lvol2.
--metadatacopies 0 option of the pvcreate
command. Once you have selected the number of metadata copies the
physical volume will contain, you cannot change that at a later point.
Selecting 0 copies can result in faster updates on configuration
changes. Note, however, that at all times every volume group must
contain at least one physical volume with a metadata area (unless you
are using the advanced configuration settings that allow you to store
volume group metadata in a file system). If you intend to split the
volume group in the future, every volume group needs at least one
metadata copy.
--metadatasize. option of the pvcreate command. The default size is too small for volume groups with many logical volumes or physical volumes.
pvcreate command places
the physical volume label in the 2nd 512-byte sector. This label can
optionally be placed in any of the first four sectors, since the LVM
tools that scan for a physical volume label check the first 4 sectors.
The physical volume label begins with the string LABELONE.
myvg.
# Generated by LVM2: Tue Jan 30 16:28:15 2007
contents = "Text Format Volume Group"
version = 1
description = "Created *before* executing 'lvextend -L+5G /dev/myvg/mylv /dev/sdc'"
creation_host = "tng3-1" # Linux tng3-1 2.6.18-8.el5 #1 SMP Fri Jan 26 14:15:21 EST 2007 i686
creation_time = 1170196095 # Tue Jan 30 16:28:15 2007
myvg {
id = "0zd3UT-wbYT-lDHq-lMPs-EjoE-0o18-wL28X4"
seqno = 3
status = ["RESIZEABLE", "READ", "WRITE"]
extent_size = 8192 # 4 Megabytes
max_lv = 0
max_pv = 0
physical_volumes {
pv0 {
id = "ZBW5qW-dXF2-0bGw-ZCad-2RlV-phwu-1c1RFt"
device = "/dev/sda" # Hint only
status = ["ALLOCATABLE"]
dev_size = 35964301 # 17.1491 Gigabytes
pe_start = 384
pe_count = 4390 # 17.1484 Gigabytes
}
pv1 {
id = "ZHEZJW-MR64-D3QM-Rv7V-Hxsa-zU24-wztY19"
device = "/dev/sdb" # Hint only
status = ["ALLOCATABLE"]
dev_size = 35964301 # 17.1491 Gigabytes
pe_start = 384
pe_count = 4390 # 17.1484 Gigabytes
}
pv2 {
id = "wCoG4p-55Ui-9tbp-VTEA-jO6s-RAVx-UREW0G"
device = "/dev/sdc" # Hint only
status = ["ALLOCATABLE"]
dev_size = 35964301 # 17.1491 Gigabytes
pe_start = 384
pe_count = 4390 # 17.1484 Gigabytes
}
pv3 {
id = "hGlUwi-zsBg-39FF-do88-pHxY-8XA2-9WKIiA"
device = "/dev/sdd" # Hint only
status = ["ALLOCATABLE"]
dev_size = 35964301 # 17.1491 Gigabytes
pe_start = 384
pe_count = 4390 # 17.1484 Gigabytes
}
}
logical_volumes {
mylv {
id = "GhUYSF-qVM3-rzQo-a6D2-o0aV-LQet-Ur9OF9"
status = ["READ", "WRITE", "VISIBLE"]
segment_count = 2
segment1 {
start_extent = 0
extent_count = 1280 # 5 Gigabytes
type = "striped"
stripe_count = 1 # linear
stripes = [
"pv0", 0
]
}
segment2 {
start_extent = 1280
extent_count = 1280 # 5 Gigabytes
type = "striped"
stripe_count = 1 # linear
stripes = [
"pv1", 0
]
}
}
}
}
| Revision History | |||
|---|---|---|---|
| Revision 6.0-1 | Wed Nov 10 2010 | ||
| |||