On 15/03/16 02:12 PM, Ferenc Wágner wrote: > Hi, > > I'm referring here to an ancient LKML thread introducing DLM. In > http://article.gmane.org/gmane.linux.kernel/299788 David Teigland > states: > > GFS requires that a failed node be fenced prior to gfs being told to > begin recovery for that node > > which sounds very plausible as according to that thread DLM itself does > not make sure fencing happens before DLM recovery, thus DLM locks could > be granted to others before the failed node is fenced (if at all). > > Now more than ten years passed and I wonder > > 1. if the above is still true (or maybe my interpretation was wrong to > start with)
Yes, fencing is required. DLM will not begin recovery until it is told that the lost node is confirmed fenced. > 2. how it is arranged for in the GFS2 code (I failed to find it with > naive search phrases) > > 3. whether clvmd does the same Anything that uses DLM requires fencing, which includes clustered LVM. (Really, all clusters require fencing to avoid split-brains). > 4. what are the pros/cons of disabling DLM fencing (even the dlm_stonith > proxy) and leaving fencing fully to the resource manager (Pacemaker) Pacemaker's fencing will inform DLM when the node has been terminated. If EL6-based clusters, this is done via 'fence_pcmk' config in cman's cluster.conf (which simply asks pacemaker to do the fence and report back when successful). -- Digimer Papers and Projects: https://alteeve.ca/w/ What if the cure for cancer is trapped in the mind of a person without access to education? _______________________________________________ Users mailing list: Users@clusterlabs.org http://clusterlabs.org/mailman/listinfo/users Project Home: http://www.clusterlabs.org Getting started: http://www.clusterlabs.org/doc/Cluster_from_Scratch.pdf Bugs: http://bugs.clusterlabs.org