> -----Original Message----- > From: ceph-users [mailto:ceph-users-boun...@lists.ceph.com] On Behalf Of > Eugen Block > Sent: 22 November 2016 09:55 > To: ceph-users@lists.ceph.com > Subject: [ceph-users] deep-scrubbing has large impact on performance > > Hi list, > > I've been searching the mail archive and the web for some help. I tried the > things I found, but I can't see the effects. We use Ceph for > our Openstack environment. > > When our cluster (2 pools, each 4092 PGs, in 20 OSDs on 4 nodes, 3 > MONs) starts deep-scrubbing, it's impossible to work with the VMs. > Currently, the deep-scrubs happen to start on Monday, which is unfortunate. I > already plan to start the next deep-scrub on Saturday, > so it has no impact on our work days. But if I imagine we had a large > multi-datacenter, such performance breaks are not reasonable. So > I'm wondering how do you guys manage that? > > What I've tried so far: > > ceph tell osd.* injectargs '--osd_scrub_sleep 0.1' > ceph tell osd.* injectargs '--osd_disk_thread_ioprio_priority 7' > ceph tell osd.* injectargs '--osd_disk_thread_ioprio_class idle' > ceph tell osd.* injectargs '--osd_scrub_begin_hour 0' > ceph tell osd.* injectargs '--osd_scrub_end_hour 7' > > And I also added these options to the ceph.conf. > To be able to work again, I had to set the nodeep-scrub option and unset it > when I left the office. Today, I see the cluster deep- > scrubbing again, but only one PG at a time, it seems that now the default for > osd_max_scrubs is working now and I don't see major > impacts yet. > > But is there something else I can do to reduce the performance impact?
If you are using Jewel, the scrubing is now done in the client IO thread, so those disk thread options won't do anything. Instead there is a new priority setting, which seems to work for me, along with a few other settings. osd_scrub_priority = 1 osd_scrub_sleep = .1 osd_scrub_chunk_min = 1 osd_scrub_chunk_max = 5 osd_scrub_load_threshold = 5 Also enabling the weighted priority queue can assist the new priority options osd_op_queue = wpq > I just found [1] and will have a look into it. > > [1] http://prob6.com/en/ceph-pg-deep-scrub-cron/ > > Thanks! > Eugen > > -- > Eugen Block voice : +49-40-559 51 75 > NDE Netzdesign und -entwicklung AG fax : +49-40-559 51 77 > Postfach 61 03 15 > D-22423 Hamburg e-mail : ebl...@nde.ag > > Vorsitzende des Aufsichtsrates: Angelika Mozdzen > Sitz und Registergericht: Hamburg, HRB 90934 > Vorstand: Jens-U. Mozdzen > USt-IdNr. DE 814 013 983 > > _______________________________________________ > ceph-users mailing list > ceph-users@lists.ceph.com > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com _______________________________________________ ceph-users mailing list ceph-users@lists.ceph.com http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
