Hi all, Wondering if anyone has come up with a quick and minimal impact way of moving data between erasure coded pools? We want to shrink an existing EC pool (also changing the EC profile at the same time) that backs our main RGW buckets. Thus far the only successful way I've found of managing the switch-over uses rados cppool like: 1) stop radosgw services 2) rados cppool <oldpool> <newpool> 3) ceph osd pool rename <oldpool> <oldpool>.old 4) ceph osd pool rename <newpool> <oldpool> 5) start radosgw services This is slow and error prone. From what I can tell it actually transfers the data between the pools via the client. Not good. Also means radosgw service is offline throughout the transfer. My next idea was to use cache tiering, but the obvious process there (insert new pool as backing under old pool as cache) doesn't work because the cache tier cannot be erasure coded. I'm now wondering if it would be feasible to: 1) insert a large enough temporary replicated pool as a cache tier 2) somehow force promotion of every object into the cache (don't see any way to do that other than actually read them - but at least some creative scripting could do that in parallel) 3) once #objects in cache = #objects in old backing pool then stop radosgw services 4) remove overlay and tier remove 6) now we should have identical or newer data in the temporary replicated pool and no caching relationship then add the temporary replicated pool as a tier (--force-nonempty) to the new EC pool 7) finally cache-flush-evict-all and remove the temporary replicated pool I'm starting to work through testing this now but would appreciate if anyone can save me some time or suggest a better option. -- Cheers, ~Blairo _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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