Hi,
I have a pair of incus servers, on Rocky 9, with a shared NVME/TCP LUN which is used for an lvmcluster storage pool.
# incus storage show san
config:
size: "3298530689024"
description: ""
name: san
driver: lvmcluster
used_by:
- /1.0/instances/stunning-hare
- /1.0/instances/touched-mako
- /1.0/storage-pools/san/volumes/custom/sanblocktest
- /1.0/storage-pools/san/volumes/custom/santest
status: Created
locations:
- incus1
- incus2
The lvmcluster pool works perfectly well for
creating custom volumes, both filesystem and block types, as you can see here:
# incus storage volume list san
+-----------+---------------+-------------+--------------+---------+----------+
| TYPE | NAME | DESCRIPTION | CONTENT-TYPE | USED BY | LOCATION |
+-----------+---------------+-------------+--------------+---------+----------+
| container | stunning-hare | | filesystem | 1 | |
+-----------+---------------+-------------+--------------+---------+----------+
| custom | sanblocktest | | block | 0 | |
+-----------+---------------+-------------+--------------+---------+----------+
| custom | santest | | filesystem | 0 | |
+-----------+---------------+-------------+--------------+---------+----------+
use as a backing store for containers.
However, I cannot launch or create an VM using it as a storage pool, with some very curious errors:
# incus launch rocky-9-cloud --storage san --target incus1
Launching the instance
Error: Failed creating instance from image: Failed to mount LVM logical volume: Failed to mount "/dev/dm-13" on "/var/lib/incus/storage-pools/san/virtual-machines/humble-owl.incustmp" using "btrfs": no such device
# incus create --vm --empty emptyvmtest --storage san
Creating emptyvmtest
Error: Failed creating instance: Failed to mount LVM logical volume: Failed to mount "/dev/dm-17" on "/var/lib/incus/storage-pools/san/virtual-machines/emptyvmtest.incustmp" using "btrfs": no such device
watching the system, I see the volumes being created and then disappearing…
Every 2.0s: lvs pstore incus2: Thu Jun 18 12:57:39 2026
LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert
containers_stunning--hare pstore -wi-ao---k 10.00g
containers_touched--mako pstore -wi-ao---k 10.00g
custom_default_sanblocktest.block pstore -wi------k 10.00g
custom_default_santest pstore -wi------k 10.00g
virtual-machines_organic--aphid pstore -wi------k 500.00m <--
virtual-machines_organic--aphid.block pstore -wi------k 10.00g <--
Changing the default filesystem used by the storage pool to “ext4” rather than “btrfs” makes no difference. It seems like incus is attempting to mount the LV as a BTRFS filesystem, but it’s supposed to be a block device, so I find that curious.
Any ideas? Or tips how I should debug this. strace is unhelpful.