On Thu, 1 Mar 2018 09:11:21 -0500, Jason Dillaman wrote: > It's very high on our priority list to get a solution merged in the > upstream kernel. There was a proposal to use DLM to distribute the PGR > state between target gateways (a la the SCST target) and it's quite > possible that would have the least amount of upstream resistance since > it would work for all backends and not just RBD. We, of course, would > love to just use the Ceph cluster to distribute the state information > instead of requiring a bolt-on DLM (with its STONITH error handling), > but we'll take what we can get (merged). I'm also very keen on having a proper upstream solution for this. My preference is still to proceed with PR state backed by Ceph. > I believe SUSE uses a custom downstream kernel that stores the PGR > state in the Ceph cluster but requires two round-trips to the cluster > for each IO (first to verify the PGR state and the second to perform > the IO). The PetaSAN project is built on top of these custom kernel > patches as well, I believe. Maged from PetaSAN added support for rados-notify based PR state retrieval. Sill, in the end the PR patch-set is too intrusive to make it upstream, so we need to work on a proper upstreamable solution, with tcmu-runner or otherwise. Cheers, David _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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