On Thu, Feb 23, 2012 at 11:00 AM, Tommi Virtanen <tommi.virtanen@xxxxxxxxxxxxx> wrote: > On Thu, Feb 23, 2012 at 01:15, Дениска-редиска <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. Actually the OSDs will happily (well, not happily; the will complain. But they will run) run in degraded mode. However, if you have 3 active MDSes and you kill one of them without a standby available, you will lose access to part of your tree. That's probably what happened here... -Greg -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
