On Fri, Jun 22, 2018 at 10:44 PM Gregory Farnum <gfarnum@xxxxxxxxxx> wrote: > > On Fri, Jun 22, 2018 at 6:22 AM Sergey Malinin <hell@xxxxxxxxxxx> 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... -- dan > -Greg > >> >> >> On 22.06.2018, at 16:16, Dan van der Ster <dan@xxxxxxxxxxxxxx> 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@xxxxxxxxxxxxxx >> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com >> >> >> _______________________________________________ >> ceph-users mailing list >> ceph-users@xxxxxxxxxxxxxx >> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > > _______________________________________________ > ceph-users mailing list > ceph-users@xxxxxxxxxxxxxx > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
 |