[DRBD-user] 2 node clustersplit-brain on linstor_db

[Roland Kammerer]

On Thu, Jun 10, 2021 at 03:20:30PM +0200, Martin wrote:
> thank you for explanation,
> 
> i have configured proxmox with 2 identical servers with nvme ssd´s  and
> a third qdevice on raspi4.
> I assumed (maybe wrong) that this would be enough.  I will try again
> with a small third diskless device
> may be raspi is enough for that ?

It should be. It just was not active, at least the status output from
your last mail only showed 2 nodes for the linstor_db resource but not a
3rd one. You can manually 'linstor resource create' it on the third
node.

> After reboot both nodes (with drbd-reactor and linstor services active) it ends
> up with the situation i described.

If you boot both at the same time yes, maybe you really end up in that
situation as the resource is not connected yet, and both will be allowed
to become Primary in that case as they have "quourum" are not connected
yet and don't know better. But if you would have used proper quorum as
described in the documentation it should not have tried to promote, as 1
out of 3 is not good enough.

> Years ago i´ve build a 2 node Cluster with drdb and proxmox. It was relativ
> easy to install dbrd (apt install .. edit the config files).  It works very well
> without a third node or qdevice.

Feel free to still do that if it better fits your scenario.

> But i use fencing via powerswitch.

Coolio, do that then.

> Because of the very good experience with drbd in the passt i try to get it running
> instead of using CEPH.

Thanks a lot, I guess we owe you! *upside down emoji*

Best, rck