On Tue, Mar 21, 2017 at 1:54 PM, Kjetil Jørgensen <kjetil@xxxxxxxxxxxx> wrote: >> c. Reads can continue from the single online OSD even in pgs that >> happened to have two of 3 osds offline. >> > > Hypothetically (This is partially informed guessing on my part): > If the survivor happens to be the acting primary and it were up-to-date at > the time, > it can in theory serve reads. (Only the primary serves reads). It makes no sense that only the primary could serve reads. That would mean that even if only a single OSD failed, all PGs for which that OSD was primary would be unreadable. There must be an algorithm to appoint a new primary. So in a 2 OSD failure scenario, a new primary should be appointed after the first failure, no? Would the final remaining OSD not appoint itself as primary after the 2nd failure? This make sense in the context of CEPH's synchronous writes too. A write isn't complete until all 3 OSDs in the PG have the data, correct? So shouldn't any one of them be able to act as primary at any time? I don't see how that would change even if 2 of 3 ODS fail at exactly the same time. _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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