There was a good discussion of this a month ago: https://www.mail-archive.com/ceph-users%40lists.ceph.com/msg11483.html That'll give you some things you can try, and information on how to undo it if it does cause problems. You can disable the warning by adding this to the [mon] section of ceph.conf: mon warn on legacy crush tunables = false On Thu, Aug 21, 2014 at 7:17 AM, Gerd Jakobovitsch <gerd at mandic.net.br> wrote: > Dear all, > > I have a ceph cluster running in 3 nodes, 240 TB space with 60% usage, > used by rbd and radosgw clients. Recently I upgraded from emperor to > firefly, and I got the message about legacy tunables described in > http://ceph.com/docs/master/rados/operations/crush-map/#tunables. After > some data rearrangement to minimize risks, I tried to apply the optimal > settings. This resulted in 28% of object degradation, much more than I > expected, and worse, I lost communication for the rbd clients, running in > kernels 3.10 or 3.11. > > Searching for a solution, I got to this proposed solution: > https://www.mail-archive.com/ceph-users at lists.ceph.com/msg11199.html. > Applying it (before the data was all moved), I got additional 2% of object > degradation, but the rbd clients came back into working. But then I got a > large number of degraded or staled PGs, that are not backfilling. Looking > for the definition of chooseleaf_vary_r, I reached the definition in > http://ceph.com/docs/master/rados/operations/crush-map/: > "chooseleaf_vary_r: Whether a recursive chooseleaf attempt will start with > a non-zero value of r, based on how many attempts the parent has already > made. Legacy default is 0, but with this value CRUSH is sometimes unable to > find a mapping. The optimal value (in terms of computational cost and > correctness) is 1. However, for legacy clusters that have lots of existing > data, changing from 0 to 1 will cause a lot of data to move; a value of 4 > or 5 will allow CRUSH to find a valid mapping but will make less data move." > > Is there any suggestion to handle it? Have I to set chooseleaf_vary_r to > some other value? Will I lose communication with my rbd clients? Or should > I return to legacy tunables? > > Regards, > > Gerd Jakobovitsch > > > _______________________________________________ > ceph-users mailing list > ceph-users at lists.ceph.com > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.ceph.com/pipermail/ceph-users-ceph.com/attachments/20140821/49a6a2c0/attachment.htm>
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