[ClusterLabs] Another word of warning regarding VirtualDomain and BtrFS (SLES15 SP2)

[Ulrich Windl]

Hi!

Another word of warning regarding VirtualDomain: While configuring a 3-node cluster with SLES15 SP2 for Xen PVM (using libvirt and the VirtaulDOmain RA), I had created a TestVM using BtrFS.
At some time of testing the cluster ended with the testVM running on more than one node (for reasons still to examine). Only after a "crm resource refresh" (rebprobe) the cluster tried to fix the problem.
Well at some point the VM wouldn't start any more, because the BtrFS used for all (SLES default) was corrupted in a way that seems unrecoverable, independenlty of how many subvolumes and snapshots of those may exist.

Initially I would guess the libvirt stack and VirtualDomain is less reliable than the old Xen method and RA.

Regards,
Ulrich