On Mon, Jun 25, 2018 at 12:34 AM Dan van der Ster <d...@vanderster.com> wrote:
> On Fri, Jun 22, 2018 at 10:44 PM Gregory Farnum <gfar...@redhat.com> > wrote: > > > > On Fri, Jun 22, 2018 at 6:22 AM Sergey Malinin <h...@newmail.com> wrote: > >> > >> From > http://docs.ceph.com/docs/mimic/rados/troubleshooting/troubleshooting-pg/ > : > >> > >> "Now 1 knows that these object exist, but there is no live ceph-osd who > has a copy. In this case, IO to those objects will block, and the cluster > will hope that the failed node comes back soon; this is assumed to be > preferable to returning an IO error to the user." > > > > > > This is definitely the default and the way I recommend you run a > cluster. But do keep in mind sometimes other layers in your stack have > their own timeouts and will start throwing errors if the Ceph library > doesn't return an IO quickly enough. :) > > Right, that's understood. This is the nice behaviour of virtio-blk vs > virtio-scsi: the latter has a timeout but blk blocks forever. > On 5000 attached volumes we saw around 12 of these IO errors, and this > was the first time in 5 years of upgrades that an IO error happened... > Did you ever get more info about this? An unexpected EIO return-to-clients turned up on the mailing list today (http://tracker.ceph.com/issues/24875) but in a brief poke around I didn't see anything about missing objects doing so. -Greg > > -- dan > > > > -Greg > > > >> > >> > >> On 22.06.2018, at 16:16, Dan van der Ster <d...@vanderster.com> wrote: > >> > >> Hi all, > >> > >> Quick question: does an IO with an unfound object result in an IO > >> error or should the IO block? > >> > >> During a jewel to luminous upgrade some PGs passed through a state > >> with unfound objects for a few seconds. And this seems to match the > >> times when we had a few IO errors on RBD attached volumes. > >> > >> Wondering what is the correct behaviour here... > >> > >> Cheers, Dan > >> _______________________________________________ > >> ceph-users mailing list > >> ceph-users@lists.ceph.com > >> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > >> > >> > >> _______________________________________________ > >> ceph-users mailing list > >> ceph-users@lists.ceph.com > >> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > > > > _______________________________________________ > > ceph-users mailing list > > ceph-users@lists.ceph.com > > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com >
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