On Tue, 23 Dec 2014, Ren? Gallati wrote: > Hello, > > so I upgraded my cluster from 89 to 90 and now I get: > > ~# ceph health > HEALTH_WARN too many PGs per OSD (864 > max 300) > > That is a new one. I had too few but never too many. Is this a problem that > needs attention, or ignorable? Or is there even a command now to shrink PGs? It's a new warning. You can't reduce the PG count without creating new (smaller) pools and migrating data. You can ignore the message, though, and make it go away by adjusting the 'mon pg warn max per osd' (defaults to 300). Having too many PGs increases the memory utilization and can slow things down when adapting to a failure, but certainly isn't fatal. > The message did not appear before, I currently have 32 OSDs over 8 hosts and 9 > pools, each with 1024 PG as was the recommended number according to the OSD * > 100 / replica formula, then round to next power of 2. The cluster has been > increased by 4 OSDs, 8th host only days before. That is to say, it was at 28 > OSD / 7 hosts / 9 pools but after extending it with another host, ceph 89 did > not complain. > > Using the formula again I'd actually need to go to 2048PGs in pools but ceph > is telling me to reduce the PG count now? The guidance in the docs is (was?) a bit confusing. You need to take the *total* number of PGs and see how many of those per OSD there are, not create as many equally-sized pools as you want. There have been several attempts to clarify the language to avoid this misunderstanding (you're definitely not the first). If it's still unclear, suggestions welcome! sage _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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