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 <[email protected]> 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 > [email protected] > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com >
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