I think the problem is that Ceph requires a certain number of OSDs or a certain number of reports of failure before it marks an OSD down. These thresholds are not tuned for a 2-OSD cluster; you probably want to set them to 1. Also keep in mind that the OSDs provide a grace period of 20-30 seconds before they'll report somebody down; this helps prevent spurious recovery but means you will get paused IO on an unclean shutdown.
I can't recall the exact config options off-hand, but it's something like "mon osd min down reports". Search the docs for that. :) -Greg On Thursday, September 29, 2016, Peter Maloney < [email protected]> wrote: > On 09/29/16 14:07, Ranjan Ghosh wrote: > > Wow. Amazing. Thanks a lot!!! This works. 2 (hopefully) last questions > > on this issue: > > > > 1) When the first node is coming back up, I can just call "ceph osd up > > 0" and Ceph will start auto-repairing everything everything, right? > > That is, if there are e.g. new files that were created during the time > > the first node was down, they will (sooner or later) get replicated > > there? > Nope, there is no "ceph osd up <id>"; you just start the osd, and it > already gets recognized as up. (if you don't like this, you set it out, > not just down; and there is a "ceph osd in <id>" to undo that.) > > > > 2) If I don't call "osd down" manually (perhaps at the weekend when > > I'm not at the office) when a node dies - did I understand correctly > > that the "hanging" I experienced is temporary and that after a few > > minutes (don't want to try out now) the node should also go down > > automatically? > I believe so, yes. > > Also, FYI, RBD images don't seem to have this issue, and work right away > on a 3 osd cluster. Maybe cephfs would also work better with a 3rd osd, > even an empty one (weight=0). (and I had an unresolved issue testing the > same with cephfs on my virtual test cluster) > > > > BR, > > Ranjan > > > > > > Am 29.09.2016 um 13:00 schrieb Peter Maloney: > >> > >> And also you could try: > >> ceph osd down <osd id> > > > > _______________________________________________ > ceph-users mailing list > [email protected] <javascript:;> > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com >
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