On 06/26/17 11:36, Marco Gaiarin wrote: > ... > Three question: > > a) while a 'snapshot remove' action put system on load? > > b) as for options like: > > osd scrub during recovery = false > osd recovery op priority = 1 > osd recovery max active = 5 > osd max backfills = 1 > > (for recovery), there are option to reduce the impact of a stapshot > remove? > > c) snapshot are handled differently from other IO ops, or doing some > similar things (eg, a restore from a backup) i've to expect some > similar result? > > > Thanks. > You also have to set: > osd_pg_max_concurrent_snap_trims=1 > osd_snap_trim_sleep=0 2nd is default 0, but just make sure. Or maybe it doesn't exist in hammer. It's bugged in jewel, and holds a lock during sleep, so you have to set it 0. And I think maybe this helps a little: > filestore_split_multiple=8 And this one lower can make performance lower, but can reduce blocked requests (due to blocking locks): > osd_op_threads = 2 (currently I have 8 set on the last one... long ago I found that lowest was the minimum bareable when doing snapshots and snap removal) And keep in mind all the "priority" stuff possibly doesn't have any effect without the cfq disk scheduler (at least in hammer... I think I've heard different for jewel and later). Check with: > grep . /sys/block/*/queue/scheduler -- -------------------------------------------- Peter Maloney Brockmann Consult Max-Planck-Str. 2 21502 Geesthacht Germany Tel: +49 4152 889 300 Fax: +49 4152 889 333 E-mail: peter.maloney@xxxxxxxxxxxxxxxxxxxx Internet: http://www.brockmann-consult.de -------------------------------------------- _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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