[NFS-Ganesha-Support] Re: Deploying an Active/Active NFS Cluster over CephFS

The main thing is that luminous does not have some of the new recovery interfaces in nautilus: A ganesha server acts as a Ceph client and any state held by it (opens, locks, etc) is tied to the ceph client session. When a ganesha restarts, the new instance of the server will need to reacquire some subset of the caps it held before, but to the Ceph MDS, it just looks like another client. So, we end up having to wait around until the old session times out before we can acquire some of those caps. That timeout is around 60s and that can eat heavily into the NFS grace period (which is usually about 90-120s). During that time, stateful operations performed by the clients (opens, locks, etc.) will stall. In nautilus we've added a way to tag a session with a particular unique ID so that when the server is resurrected it can ask the MDS to cancel the old session immediately. That allows us to get back to business quicker. Luminous may work but (at best) you'll end up with longer recovery times. At worst, you could end up with NFS state recovery failures if the interlocking timeouts didn't work out cleanly. -- Jeff On Wed, 2018-12-12 at 13:35 +0000, David C wrote: -- Jeff Layton <jlayton(a)redhat.com&gt;