How to reduce LVM partition size in RHEL and OEL

If observe a particular file system is not used fully and a lot of free space is available then we can make some free space in the volume group by reducing the LVM using lvreduce command.

Example: To reduce /oracle mount by 2GB which is on LVM partition & formated as ext4

[root@funebs122 ~]# df -h /oracle/

Filesystem Size Used Avail Use% Mounted on

/dev/mapper/vg_funebs122-lvol1

12G 9.2G 1.9G 84% /oracle

Steps:

1. Umount the file system

[root@funebs122 ~]# umount -v /oracle/

2. Check the file system for Errors using e2fsck command

[root@funebs122 ~]# e2fsck -f /dev/mapper/vg_funebs122-lvol1

e2fsck 1.41.12 (17-May-2010)

Pass 1: Checking inodes, blocks, and sizes

Pass 2: Checking directory structure

Pass 3: Checking directory connectivity

Pass 4: Checking reference counts

Pass 5: Checking group summary information

/dev/mapper/vg_funebs122-lvol1: 12/70640 files (0.0% non-contiguous), 446686/308428 blocks

Note: In the above command e2fsck , we use the option ‘-f’ to forcefully check the file system, even if the file system is clean.

3. Reduce or Shrink the size of /oracle to the desire size.

In my case size of /oracle is 12 GB , so by reducing it by 2GB , then the size will become 10GB.

[root@funebs122 ~]# resize2fs /dev/mapper/vg_funebs122-lvol1 10G

resize2fs 1.41.12 (17-May-2010)

Resizing the filesystem on /dev/mapper/vg_funebs122-lvol1 to 2621440 (4k) blocks.

The filesystem on /dev/mapper/vg_funebs122-lvol1 is now 2621440 blocks long.

4. Reduce the size using lvreduce command

[root@funebs122 ~]# lvreduce -L 10G /dev/mapper/vg_funebs122-lvol1

WARNING: Reducing active logical volume to 10.00 GiB

THIS MAY DESTROY YOUR DATA (filesystem etc.)

Do you really want to reduce lvol1? [y/n]: y

Reducing logical volume lvol1 to 10.00 GiB

Logical volume lvol1 successfully resized

5. Now check the reduced file system for errors (Optional)

[root@funebs122 ~]# e2fsck -f /dev/mapper/vg_funebs122-lvol1

e2fsck 1.41.12 (17-May-2010)

Pass 1: Checking inodes, blocks, and sizes

Pass 2: Checking directory structure

Pass 3: Checking directory connectivity

Pass 4: Checking reference counts

Pass 5: Checking group summary information

/dev/mapper/vg_funebs122-lvol1: 12/70640 files (0.0% non-contiguous), 446686/308428 blocks

6. Mount the file system and verify its size.

[root@funebs122 ~]# mount /oracle/

[root@funebs122 ~]# df -h /oracle/

Filesystem Size Used Avail Use% Mounted on

/dev/mapper/vg_funebs122-lvol1

9.9G 9.2G 208M 98% /oracle

Note for XFS file system:

While the XFS file systems can be grown while mounted, their size cannot be reduced.

Workarounds may be done:

Use some backup/restore solution, such as xfsdump and xfsrestore. This may be useful especially if the filesystem is mostly empty.

Use the xfs_quota command to implement project (directory tree) quotas. Project quotas implement space limitations for all files within a directory subtree, similar to behavior under a new filesystem mount point.