On Thu, 23 Feb 2012, Tommi Virtanen wrote: > On Thu, Feb 23, 2012 at 01:15, ÿÿÿÿÿÿÿÿÿÿÿÿÿÿ-ÿÿÿÿÿÿÿÿÿÿÿÿÿÿ <slim@xxxxxxxx> wrote: > > ehllo here, > > > > i have tried to setup ceph .41 in simple configuration: > > 3 nodes, each running mon, mds & osd with replication level 3 for data & metadata pools. > > Each node mounts ceph locally via ceph-fuse > > cluster seems running well until one of the nodes goes down for simple reboot. > > Then all mount points become inaccessible, data transfer hangs and cluster stop working > > > > What is the purpose of ceph software while such simple case does not go through ? > > You have a replication factor of 3, and 3 OSDs. If one of them is > down, the replication factor of 3 cannot be satisfied anymore. You > need either more nodes, or a smaller replication factor. > > Ceph is not an eventually consistent system; building a POSIX > filesystem on top of one is pretty much impossible. With Ceph, all > replicas are always kept up to date. Just to clarify: what should have happend is that after a few seconds (20 by default?) the stopped ceph-osd is marked down and life continues with 2 replicas. 'ceph -s' or 'ceph health' will report some PGs in the 'degraded' state. sage
