Am 19.12.2013 um 20:39 schrieb Wolfgang Hennerbichler <wo...@wogri.com>: > On 19 Dec 2013, at 16:43, Gruher, Joseph R <joseph.r.gru...@intel.com> wrote: > >> It seems like this calculation ignores that in a large Ceph cluster with >> triple replication having three drive failures doesn't automatically >> guarantee data loss (unlike a RAID6 array)? > > not true with RBD images, which are potentially striped across the whole > cluster.
Even in this case it only results in data loss if all three existing copies of the data are affected. In a large cluster this is very unlikely with only three disks. Three succeeding disk failures are getting „common“ if the cluster size is large enough, but it will usually only affect disks serving disjoint set of PGs, so for each disk there are still enough copies. regards Johannes _______________________________________________ ceph-users mailing list ceph-users@lists.ceph.com http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
