How to reduce LVM partition size in RHEL and OEL

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.

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