How to reduce a LVM partition in linux

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Here is the short tutorial, which explains how to reduce a LVM partition in linux. Before we proceed, please check the configuration of my server.

Harddisk Partition /dev/sda1 & /dev/sdb1 both partitions are 2GB each.
Volume group jg_sda
Logical volume media – size 2 GiB
Address of the logical volume is /dev/jg_sda/media

Reducing a logical volume

Task : Reduce the logical volume /dev/jg_sda/media from 2GB to 1 GB size.

Reducing a logical volume involves following 3 steps namely –

01. Unmount the logical volume (if it is mounted)
02. Reduce the file system residing on the logical volume. And finally,
03. Reduce the logical volume.

Step 1 – Unmount the logical volume

If the logical volume is not mounted anywhere, you can skip this step.

Since our logical volume has been mounted at /mnt/volume, we have to unmount it.

[root@24x7serversolutions ~]# umount /mnt/volume

Step 2 – Reduce the file system residing on the logical volume

First run e2fsck to check the file system as follows –

[root@24x7serversolutions ~]# e2fsck -f /dev/jg_sda/media

Next resize the filesystem on the logical volume to 1 GB size using the resize2fs command.

[root@24x7serversolutions ~]# resize2fs /dev/jg_sda/media 1G
Resizing the filesystem on /dev/jg_sda/media to 262144 (4k) blocks.
The filesystem on /dev/jg_sda/media is now 262144 blocks long.

Step 3 – Reduce the logical volume

To reduce the size of a logical volume, we use the lvreduce LVM command.

Now lets reduce the logical volume /dev/jg_sda/media from 2 GB to 1 GB.

[root@24x7serversolutions ~]# lvreduce --size 1G /dev/jg_sda/media
WARNING: Reducing active logical volume to 1.00 GiB
THIS MAY DESTROY YOUR DATA (filesystem etc.)
Do you really want to reduce media? [y/n]: y
Reducing logical volume media to 1.00 GiB
Logical volume media successfully resized.

Re-size the file-system back, In this step if there is any error that means we have messed-up our file-system.

[root@24x7serversolutions ~]# resize2fs /dev/jg_sda/media

Mount the file-system back to same point.
[root@24x7serversolutions ~]#mount /dev/jg_sda/media /mnt/volume