On Thu, Jul 22, 2021 at 12:43 PM Jehan-Guillaume de Rorthais <j...@dalibo.com> wrote: > > On Wed, 21 Jul 2021 12:45:40 -0400 > Digimer <li...@alteeve.ca> wrote: > > > On 2021-07-21 3:26 a.m., Jehan-Guillaume de Rorthais wrote: > > > Hi, > > > > > > On Wed, 21 Jul 2021 04:28:30 +0000 (UTC) > > > Strahil Nikolov via Users <users@clusterlabs.org> wrote: > > > > > >> Hi, > > >> consider using a 3rd system as a Q disk. Also, you can use iscsi from > > >> that > > >> node as a SBD device, so you will have proper fencing .If you don't have > > >> a > > >> hardware watchdog device, you can use softdog kernel module for that. > > >> Best > > > > > > Having 3 nodes for quorum AND watchdog (using softdog in last resort) is > > > enough, isn't it? > > > But yes, having a shared storage to add a SBD device is even better. > > > > > > Regards, > > > > The third node with storage-based death is a way of creating a fence > > configuration. > > Yes, poison pill. > > > It works because it's fencing, not because it's quorum. > > That's not what I said. Two node + sbd is safe. OK. > > My consideration/question was: 3 nodes + watchdog, without storage-based > death, > looks good enough to me. Do I miss something? >
>From an integrity point of view it is equivalent to SBD. SBD at the end relies on a watchdog as well. So if you have a reliable hardware watchdog it should be OK. >From an operational point of view pacemaker does not have the notion of "cluster wide shutdown". Which means - as soon as you stop pacemaker on two nodes the third node will commit suicide because it goes out of quorum. Last man standing may help here, I have not tried it in true three node cluster. This does not happen with SBD as long as storage remains accessible. _______________________________________________ Manage your subscription: https://lists.clusterlabs.org/mailman/listinfo/users ClusterLabs home: https://www.clusterlabs.org/
