[DRBD-user] Linstor | Failed to restore snapshot

[Roland Kammerer]

On Fri, Aug 24, 2018 at 02:27:09PM +0200, Robert Altnoeder wrote:
> On 08/24/2018 02:07 PM, Yannis Milios wrote:
> > [...]
> >
> > When trying to restore the snapshot from the command line to a new
> > resource (vm-120-disk-1), as described in the documentation,
> > I'm getting the error below...
> >
> > [...]
> >
> >     Error message: 
> >       Snapshot origin LV vm-122-disk-1_00000_snap_vm-122-disk-1_snap1
> > not found in Volume group drbdpool.
> >
> >
> > ...Where the actual snapshot name in the drbdpool VG is (note the two
> > 00 instead of four above): 
> >
> > LV Name    vm-122-disk-1_00_snap_vm-122-disk-1_snap1
> >
> > Could this be a bug ?
> 
> All those names seem suspicious. We will check whether there is a
> rationale for this format or the names got messed up somehow. The _00
> volume number is certainly suspicious too. Drbdmanage used to expand
> single-digit volume numbers to 2 digits, whereas LINSTOR was supposed to
> always use 5 digit volume numbers (this was done so that other software
> could easily sort backend volume storage names created by LINSTOR).

I'm afraid this is somewhere in LINSTOR. The proxmox plugin just
generates snapshots (or deletes them, but never restores them). The
restore is then done by linstor (on the cli, no support in proxmox).
That must happen in combination with the migration and LINSTOR mixing up
old/new volume names.

Robert, for reference:

boring SN name generation (the "snap" part is some user input):
https://github.com/LINBIT/linstor-proxmox/blob/master/LINSTORPlugin.pm#L156

and SN creation:
https://github.com/LINBIT/linstor-proxmox/blob/master/LINSTORPlugin.pm#L424

All of that looks too boring as that the plugin could have messed up
something.

Regards, rck