>> 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@lists.ceph.com http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
