February 9, 2025

Logical Volume Management on RHEL

Here’s guide on how to work with logical volume management on RHEL

To see & rescan physical volumes

pvs

pvscan

To see & rescan volume group

vgs

vgscan

To see & rescan logical volumes

lvs

lvscan

Here’s guide on how to increase the logical volume

lvresize -r -L + ##G /dev/myvg/mylv (extend by gigabyte)

lvresize -r -l +#### /dev/myvg/mylv (extend by bytes)

lvresize -r -l +100%FREE /dev/myvg/mylv (extend by percentage)

lvextend -L #G /dev/myvg/mylv (set to specific size by gigabyte)

lvextend -L +#G /dev/myvg/mylv (extend by bytes)

lvextend -l +100%FREE /dev/myvg/mylv (extend by percentage)

*lvextend will not show any free space after the execution.

*try to run the command “resize2fs /dev/mapper/logicalVolumePath/” and check df -Ph to verify that they have free space afterwards

Here’s guide on how to reduce the logical volume

1. Shutdown all applications/databases which are hosted in the logical volume management

2. Complete the backup

3. Unmount the file system

4. Hashout the file system entry in /etc/fstab

5. It’s only applicable for ext2/ext3/ext4

6. Check for any errors (e2fsck -f “logical_volume_path”)

ex: e2fsck -f /dev/mapper/rhel_vg-lv0

7. Reduce the file system (resize2fs “logical_volume_path” “want_to_become_size”)

ex: resize2fs /dev/mapper/rhel_vg-lv0 1G

8. Reduce the logical volume size (lvreduce -L “want_to_become_size” “logical_volume_path”)

ex: lvreduce -L 1G /dev/mapper/rhel_vg-lv0

9. Uncomment on /etc/fstab

10. Mount the file system