Hi Mike, On 30.05.2017 01:49, Mike Cave wrote: > > Greetings All, > > > > I recently started working with our ceph cluster here and have been > reading about weighting. > > > > It appears the current best practice is to weight each OSD according > to it’s size (3.64 for 4TB drive, 7.45 for 8TB drive, etc). > > > > As it turns out, it was not configured this way at all; all of the > OSDs are weighted at 1. > > > > So my questions are: > > > > Can we re-weight the entire cluster to 3.64 and then re-weight the 8TB > drives afterwards at a slow rate which won’t impact performance? > > If we do an entire re-weight will we have any issues? > I would set osd_max_backfills + osd_recovery_max_active to 1 (with injectargs) before start the reweight to minimize the impact for running clients. After set all to 3.64 you can raise the weight for the 8TB-drives one by one. Depends on your cluster/OSDs, it's perhaps an good idea to adjust the primary affinity for the 8-TB drives during reweight?! Otherwise you got more reads from the (slower) 8TB-drives.
> Would it be better to just reweight the 8TB drives to 2 gradually? > I would go for 3.64 - than you have the right settings if you init further OSDs with ceph-deploy. Udo _______________________________________________ ceph-users mailing list ceph-users@lists.ceph.com http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
