I’ve created a LVM (eg. “vg1”) and set the whole space to a single group (eg. “vz”) to have plenty room for my Proxmox VMs (space directive “all” at LVM creation).
LV vg1 vz /var/lib/vz ext4 all
Upon taking cron based snapshots of running VMs, Proxmox said that there’s no space left on vg1.
I’ve got the following errors in the snapshot logs:
INFO: Volume group "vg1" has insufficient free space (0 extents): 256 required. ERROR: Backup of VM 123 failed - command 'lvcreate --size 1024M --snapshot --name 'vzsnap-virtual-0' '/dev/vg1/vz'' failed: exit code 5
LVM util “vgs vg1” shows:
root@proxmox ~ # vgs vg1 VG #PV #LV #SN Attr VSize VFree vg1 1 1 0 wz--n- 1.73t 0
Look at the value of VFree. Looks bad, 0 bytes free!
Backup all your data on your LVM VG to be shrinked before proceeding!
- Shutdown all VMs
- Stop Proxmox
- Stop all KVM processes
Unmount the vg1 LVM VG:
umount /dev/vg1/vz
You need to check the filesystem on the LVM device first:
e2fsck -f /dev/vg1/vz
After that’s passed, shrink the filesystem on vg1/vz:
resize2fs /dev/vg1/vz NEWVAL[KMG]
In my case that did the job:
root@proxmox ~ # resize2fs /dev/vg1/vz 1200G resize2fs 1.41.12 (17-May-2010) Resizing the filesystem on /dev/vg1/vz to 314572800 (4k) blocks. The filesystem on /dev/vg1/vz is now 314572800 blocks long.
The new shrinked block size on /dev/vg1/vz is now 314572800 blocks.
Let’s check if the blocksize matches by remounting the shrinked filesystem:
mount /dev/vg1/vz
Get an approximate block count for the shrinked filesystem:
root@proxmox ~ # df /var/lib/vz Filesystem 1K-blocks Used Available Use% Mounted on /dev/mapper/vg1-vz 1248378224 15409856 1170053812 2% /var/lib/vz
root@proxmox ~ # df -h /var/lib/vz Filesystem Size Used Avail Use% Mounted on /dev/mapper/vg1-vz 1.2T 15G 1.1T 2% /var/lib/vz
Looks good. The value of 1K blocks is a bit lower than the actual block size of the whole filesystem. That’s normal.
Verify the exact block size (LVM does not need to be mounted):
root@proxmox ~ # dumpe2fs -h /dev/vg1/vz|grep "Block count" dumpe2fs 1.41.12 (17-May-2010) Block count: 314572800
Looks good. Block count 314572800 matches the block count that resize2fs printed after shrinking.
Unmount filesystem!
umount /dev/vg1/vz
Resizing the LVM:
root@proxmox ~ # lvreduce --size 1200G /dev/vg1/vz WARNING: Reducing active and open logical volume to 1.17 TiB THIS MAY DESTROY YOUR DATA (filesystem etc.) Do you really want to reduce vz? [y/n]: y Reducing logical volume vz to 1.17 TiB Logical volume vz successfully resized
Final check:
root@virtual ~ # vgs vg1 VG #PV #LV #SN Attr VSize VFree vg1 1 1 0 wz--n- 1.73t 566.52gVFree tells me that there are 566.52G free. Looks good. Check shrinked filesystem:
root@proxmox ~ # e2fsck -f /dev/vg1/vz 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/vg1/vz: 37/78643200 files (0.0% non-contiguous), 6330708/314572800 blocksRemount the shrinked filesystem:
root@proxmox ~ # mount /dev/mapper/vg1-vzCheck space on shrinked filesystem:
root@proxmox ~ # df -h /var/lib/vz Filesystem Size Used Avail Use% Mounted on /dev/mapper/vg1-vz 1.2T 15G 1.1T 2% /var/lib/vz
Well. We’re done!
Benjamin Wiedmann
Benjamin Wiedmann is an IT Professional, Software Developer, Photograph and Musician. Read more...
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