Arne, Sorry this got dropped -- I had it marked in my mail but didn't have the chance to think about it seriously when you sent it. Does this still happen after the updatedb config change you guys made recently? -Greg Software Engineer #42 @ http://inktank.com | http://ceph.com On Fri, Jan 31, 2014 at 5:52 AM, Arne Wiebalck <Arne.Wiebalck@xxxxxxx> wrote: > Hi, > > We observe that we can easily create slow requests with a simple dd on > CephFS: > > --> > [root@p05153026953834 dd]# dd if=/dev/zero of=xxx bs=4M count=1000 > 1000+0 records in > 1000+0 records out > 4194304000 bytes (4.2 GB) copied, 4.27824 s, 980 MB/s > > ceph -w: > 2014-01-31 14:28:44.009543 osd.450 [WRN] 1 slow requests, 1 included below; > oldest blocked for > 31.088950 secs > 2014-01-31 14:28:44.009676 osd.450 [WRN] slow request 31.088950 seconds old, > received at 2014-01-31 14:28:12.920423: osd_op(client.16735018.1:22493091 > 100000352b3.000002e9 [write 0~4194304,startsync 0~0] 0.518f2eef snapc 1=[] > e32400) v4 currently waiting for subops from [87,1190] > <--- > > From what we see, the OSDs are not busy, so we suspect that it is the client > starting all requests, > but then the requests take longer than 30 secs to finish writing, i.e. > flushing the client-side buffers. > > Is our understanding correct? > Do these slow requests have an impact on requests from other clients, i.e. > some OSD resources > consumed by these clients? > > The setup is: > Client: kernel 3.13.0, 1GbE > MDS Emperor 0.72.2 > OSDs Dumpling 0.67.5 > > Thanks! > Dan & Arne > > > -- > Arne Wiebalck > CERN IT > > > _______________________________________________ > 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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