On Tue, Feb 18, 2014 at 8:21 AM, Dan van der Ster <daniel.vanderster@xxxxxxx> wrote: > Hi, > Today I've noticed an interesting result of not have hashpspool > enabled on a number of pools -- backfilling is delayed. > > Take for example the following case: a PG from each of 5 different > pools (details below) are all mapped to the same three OSDs: 884, > 1186, 122. This is of course bad for data distribution, but I realised > today that it also delays backfilling. In our case we have osd max > backfills = 1, so the first 4 PGs listed below all have to wait for > 32.1a1 to finish before they can start. And in this case, pool 32 has > many objects, with low importance, whereas pools 4 and 5 have high > importance data that I'd like backfilled with priority. I'm not sure if this reasoning is quite right. If you had hashpspool enabled, you would still have sets of OSDs that share PGs across each of the pools, and your max backfill params would still limit how many of them could backfill at a time. They just wouldn't be sequentially numbered. > > Is there a way (implemented or planned) to prioritise the backfilling > of certain pools over others? > If not, is there a way to instruct a given PG to begin backfilling right away? Sadly no; I don't think we've ever talked about either of these. This sounds like it would be a good feature request in the tracker, or maybe a good blueprint for the upcoming summit if you can flesh out the UI you'd like to see. > And a related question: will > ceph osd pool set <poolname> hashpspool true > be available in a dumpling release, e.g. 0.67.7? It is not available > in 0.67.5, AFAICT. We discussed it but didn't think there was much point -- if you need to enable hashpspool you can do so by extracting, manually editing, and injecting the crush map. :) -Greg > > Cheers, Dan > > 2.1bf active+degraded+remapped+wait_backfill [884,1186,122] [884,1186,1216] > > 6.1bb active+degraded+remapped+wait_backfill [884,1186,122] [884,1186,1216] > > 4.1bd active+degraded+remapped+wait_backfill [884,1186,122,841] > [884,1186,182,1216] > > 5.1bc active+degraded+remapped+wait_backfill [884,1186,122,841] > [884,1186,182,1216] > > 32.1a1 active+degraded+remapped+backfilling [884,1186,122] [884,1186,1216] > > full details at: > > http://pastebin.com/raw.php?i=LBpx5VsD > > -- Dan van der Ster || Data & Storage Services || CERN IT Department -- > _______________________________________________ > 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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