>> > >> >> >> >> Say I think my cephfs is slow when I rsync to it, slower than it >> used >> to be. First of all, I do not get why it reads so much data. >> I assume >> the file attributes need to come from the mds server, so >> the rsync >> backup should mostly cause writes not? >> >> >> > >> >Are you running one or multiple MDS? I've seen cases where the >> >synchronization between the different MDS slow down rsync. >> >> One >> >> >The problem is that rsync creates and renames files a lot. When >> doing >this with small files it can be very heavy for the MDS. >> > >> >> Strange thing is that I did not have performance problems with >> luminous, after upgrading to nautilus and enabling snapshots on a >> different tree of the cephfs. Rsync is taking 10 hours more. >> There is also another option, degrading performance on the source. >> However it is impossible for me to verify this. >> I have increased the mds_cache_memory_limit from 8GB to 16GB, see what >> that brings. >> > >how many snapshot are there ? 22 still, it is this kworker again, filed bug https://tracker.ceph.com/issues/44100?next_issue_id=44099 Looks like when I unmount and then mount again, the problem is temporary gone. >> > >> >> I think it started being slow, after enabling snapshots on the >> file >> system. >> >> >> >> - how can I determine if mds_cache_memory_limit = 8000000000 is >> still >> correct? >> >> >> >> - how can I test the mds performance from the command line, so I >> can >> >> >> experiment with cpu power configurations, and see if this brings a >> >> significant change? >> >> _______________________________________________ >> >> ceph-users mailing list -- ceph-users@xxxxxxx To unsubscribe send >> an >> >> >> email to ceph-users-leave@xxxxxxx >> >> >> > > > _______________________________________________ ceph-users mailing list -- ceph-users@xxxxxxx To unsubscribe send an email to ceph-users-leave@xxxxxxx
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