The best practice to reweight OSDs is to run test-reweight-by-utilization which is dry-run of reweighting OSDs before running reweight-by-utilization. On Sat, Dec 31, 2016 at 3:05 AM, Brian Andrus <brian.andrus@xxxxxxxxxxxxx> wrote: > We have a set it and forget it cronjob setup once an hour to keep things a > bit more balanced. > > 1 * * * * /bin/bash /home/briana/reweight_osd.sh 2>&1 | /usr/bin/logger -t > ceph_reweight > > The script checks and makes sure cluster health is OK and no other > rebalancing is going on. It will also check the reported STDDEV from `ceph > osd df` and if outside acceptable ranges executes a gentle reweight. > > ceph osd reweight-by-utilization 103 .015 10 > > It's definitely an "over time" kind of thing, but after a week we are > already seeing pretty good results. Pending OSD reboots, a few months from > now our cluster should be seeing quite a bit less difference in utilization. > > The three parameters after the reweight-by-utilization are not well > documented, but they are > > 103 - Select OSDs that are 3% above the average (default is 120 but we want > a larger pool of OSDs to choose from to get an eventual tighter tolerance) > .010 - don't reweight any OSD more than this increment (keeps the impact > low) > 10 - number of OSDs to select (to keep impact manageable) > > Hope that helps. > > On Fri, Dec 30, 2016 at 2:27 AM, Kees Meijs <kees@xxxxxxxx> wrote: >> >> Thanks, I'll try a manual reweight at first. >> >> Have a happy new year's eve (yes, I know it's a day early)! >> >> Regards, >> Kees >> >> On 30-12-16 11:17, Wido den Hollander wrote: >> > For this reason you can do a OSD reweight by running the 'ceph osd >> > reweight-by-utilization' command or do it manually with 'ceph osd reweight X >> > 0-1' >> >> _______________________________________________ >> ceph-users mailing list >> ceph-users@xxxxxxxxxxxxxx >> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > > > > > -- > Brian Andrus > Cloud Systems Engineer > DreamHost, LLC > > _______________________________________________ > 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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