Linux Logical Volume Management Operations: Difference between revisions
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Revision as of 13:13, 23 May 2017
External
- https://www.howtogeek.com/howto/40702/how-to-manage-and-use-lvm-logical-volume-management-in-ubuntu/
Internal
Overview
Logical volume management commands can be issued from the lvm console, or as standalone commands. For example:
lvm> lvs
produces identical results to
lvs
Inventory of Devices that May Be Used as Physical Volumes
lvmdiskscan
Example:
[root@rhel-test ~]# lvmdiskscan /dev/rhel_rhel-test/swap [ 820.00 MiB] /dev/sda1 [ 500.00 MiB] /dev/rhel_rhel-test/root [ 6.67 GiB] /dev/sda2 [ 7.51 GiB] LVM physical volume /dev/sdb [ 2.00 GiB] 3 disks 1 partition 0 LVM physical volume whole disks 1 LVM physical volume
The output specifies which device is already a LVM Physical Volume
To see only the existing Physical Volumes (devices that have Volume Groups on them)
lvmdiskscan -l
Details about a Specific Physical Volume
pvdisplay [PhysicalVolumePath [PhysicalVolumePath...]]
Example:
[root@rhel-test ~]# pvdisplay /dev/sda2 --- Physical volume --- PV Name /dev/sda2 VG Name rhel_rhel-test PV Size 7.51 GiB / not usable 3.00 MiB Allocatable yes (but full) PE Size 4.00 MiB Total PE 1922 Free PE 0 Allocated PE 1922 PV UUID xV16At-8wPi-wFp0-42BL-XFX0-5aJE-F471OI
Physical Volume Operations
Information about Physical Volumes
Physical Volume Management Operations
- Change attributes of physical volume
pvchange
- Resize physical volume
pvresize
- Check the consistency of physical volume
pvck
- Move extents from one physical volume to another
pvmove
- Remove LVM label(s) from physical volume(s)
pvremove
Volume Group Operations
Information about Volume Groups
vgdisplay --verbose
Volume Group Management Operations
Logical Volume Operations
Information about Logical Volumes
lvdisplay --verbose
What does this do:
lvscan
Logical Volume Management Operations
Creating a Logical Volume
lvm lvm> lvcreate --size 20G --name santorini VolGroup00
Extending a Logical Volume
Renaming a Logical Volume
lvm lvm> lvrename VolGroup00 LogVol05numbercat lv05
Removing a Logical Volume
Gather statistics on the free space before removing, and also on the size of the logical volume to be removed:
vgs
lvs
Unmount the volume if necessary (or shutdown the service that is using it, as it is the case with Docker):
umount /dev/VolGroup00/MyLV1
Remove the logical volume with lvremove.
The command has a "dry run mode" (-t):
lvremove /dev/<VG_name>/<LV_name>
lvremove -t /dev/<VG_name>/<LV_name>
Example:
[root@rhel-test lvm]# lvremove -t /dev/rhel_rhel-test/docker-pool TEST MODE: Metadata will NOT be updated and volumes will not be (de)activated. Do you really want to remove active logical volume docker-pool? [y/n]: y Logical volume "docker-pool" successfully removed
This command actually removes it:
lvremove [-v] /dev/VolGroup00/MyLV1
Shrinking the Filesystem and the Logical Volume
This is the simple case, it will only work if the logical volume *does not* contain a partition table:
fsadm
or
umount lvm_partition resize2fs /dev/vg/lv newSize lvresize -L disksize /dev/vg/lv resize2fs /dev/vg/lv