I had observed that the slow requests up to 10-20 seconds on writes may be produced immediately after creation or deletion of a snapshot of relatively large image, despite that image may be entirely unused at the moment. On Sun, Apr 21, 2013 at 7:44 PM, Gregory Farnum <greg@xxxxxxxxxxx> wrote: > Which version of Ceph are you running right now and seeing this with > (Sam reworked it a bit for Cuttlefish and it was in some of the dev > releases)? Snapshot deletes are a little more expensive than we'd > like, but I'm surprised they're doing this badly for you. :/ > -Greg > Software Engineer #42 @ http://inktank.com | http://ceph.com > > On Sun, Apr 21, 2013 at 2:16 AM, Olivier Bonvalet > <olivier.bonvalet@xxxxxxxxx> wrote: >> Hi, >> >> I have a backup script, which every night : >> * create a snapshot of each RBD image >> * then delete all snapshot that have more than 15 days >> >> The problem is that "rbd snap rm XXX" will overload my cluster for hours >> (6 hours today...). >> >> Here I see several problems : >> #1 "rbd snap rm XXX" is not blocking. The erase is done in background, >> and I know no way to verify if it was completed. So I add "sleeps" >> between rm, but I have to estimate the time it will take >> >> #2 "rbd (snap) rm" are sometimes very very slow. I don't know if it's >> because of XFS or not, but all my OSD are at 100% IO usage (reported by >> iostat) >> >> >> >> So : >> * is there a way to reduce priority of "snap rm", to avoid overloading >> of the cluster ? >> * is there a way to have a blocking "snap rm" which will wait until it's >> completed >> * is there a way to speedup "snap rm" ? >> >> >> Note that I have a too low PG number on my cluster (200 PG for 40 active >> OSD ; but I'm trying to progressivly migrate data to a newer pool). Can >> it be the source of the problem ? >> >> Thanks, >> >> Olivier >> >> _______________________________________________ >> 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
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