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 <k...@nefos.nl> 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@lists.ceph.com > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > -- Brian Andrus Cloud Systems Engineer DreamHost, LLC
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