Shrink EXT4 Volume with LVM Online – How to Reduce LVM Size on Linux

ext4hard drivelinuxlvm

Today I tried this on my machine with OpenSUSE 12.3 (kernel 3.7):

# resize2fs /dev/mapper/system-srv 2G
resize2fs 1.42.6 (21-Sep-2012)
Filesystem at /dev/mapper/system-srv is mounted on /srv; on-line resizing required
resize2fs: On-line shrinking not supported

/dev/mapper/system-srv is an EXT4 volume.

Is it really unsupported or I am missing something?

Best Answer

As the message said, you can only grow an ext4 filesystem on-line. If you want to shrink it, you will need to unmount it first.

According to the ext4 filesystem maintainer, Ted Ts'o:

Sorry, on-line shrinking is not supported.

Related Solutions

Linux – CentOS 5.5 ext4 conversion problem – ext4 partition is recognized as ext3

I solved the problem. It was because mkinitrd was called without --with=ext4 option. I posted detailed article to my blog.

Linux – LVM: resize2fs not resizing

The lvextend command you executed would only extend the filesystem by 800MB (assuming default extent size), a rounding error when you're looking at TB filesystems. The -l flag means "extents" which, by default, are 4MB in size. If you wish to grow the filesystem by, say, 200GB, the command would be: lvextend -L +200G vg2/lv_backup. (Note the difference between -l and -L.)

The problem is that the initial filesystem was 1TB (almost) and the new one is 800GB, so the new logical volume should now be around 1.8TB. From here, you can see that both the drives are part of the same volume groups:

The initial filesystem was 1TB. The new disk is 800GB. You added that disk to the VG, then used 800MB of that disk to extend the LV, then grow the filesystem on the LV, leaving you with 1.0008TB in the LV. Then you grew the filesystem to fill the LV.

If you want to end up with a 1.8TB filesystem, do this:

lvextend -L +800G vg2/lv_backup

or:

lvextend -l 100%FREE vg2/lv_backup

Followed by the resize2fs command.

Best Answer

Related Solutions

Linux – CentOS 5.5 ext4 conversion problem – ext4 partition is recognized as ext3

Linux – LVM: resize2fs not resizing

Related Topic