I’m fairly sure I saw it as recently as Hammer, definitely Firefly. YMMV. > On Mar 21, 2017, at 4:09 PM, Gregory Farnum <gfarnum@xxxxxxxxxx> wrote: > > You shouldn't need to set min_size to 1 in order to heal any more. That was the case a long time ago but it's been several major LTS releases now. :) > So: just don't ever set min_size to 1. > -Greg > On Tue, Mar 21, 2017 at 6:04 PM Anthony D'Atri <aad@xxxxxxxxxxxxxx> wrote: > >> a min_size of 1 is dangerous though because it means you are 1 hard disk failure away from losing the objects within that placement group entirely. a min_size of 2 is generally considered the minimum you want but many people ignore that advice, some wish they hadn't. > > > > I admit I am having difficulty following why this is the case > > I think we have a case of fervently agreeing. > > Setting min_size on a specific pool to 1 to allow PG’s to heal is absolutely a normal thing in certain circumstances, but it’s important to > > 1) Know _exactly_ what you’re doing, to which pool, and why > 2) Do it very carefully, changing ‘size’ instead of ‘min_size’ on a busy pool with a bunch of PG’s and data can be quite the rude awakening. > 3) Most importantly, _only_ set it for the minimum time needed, with eyes watching the healing, and set it back immediately after all affected PG’s have peered and healed. > > The danger, which I think is what Wes was getting at, is in leaving it set to 1 all the time, or forgetting to revert it. THAT is, as we used to say, begging to lose. > > — aad > > _______________________________________________ > 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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