The sizes are determined by rocksdb settings - some details can be found here: https://tracker.ceph.com/issues/24361 One thing to note, in this thread http://lists.ceph.com/pipermail/ceph-users-ceph.com/2018-October/030775.html it's noted that rocksdb could use up to 100% extra space during compaction so if you want to avoid spill over during compaction then safer values would be 6/60/600 GB
You can change max_bytes_for_level_base and max_bytes_for_level_multiplier to suit your needs better but I'm not sure if that can be changed on the fly or if you have to re-create OSDs in order to make them apply On Tue, 25 Jun 2019 at 18:06, Rafał Wądołowski <rwadolow...@cloudferro.com> wrote: > Why are you selected this specific sizes? Are there any tests/research on > it? > > > Best Regards, > > Rafał Wądołowski > > On 24.06.2019 13:05, Konstantin Shalygin wrote: > > Hi > > Have been thinking a bit about rocksdb and EC pools: > > Since a RADOS object written to a EC(k+m) pool is split into several > minor pieces, then the OSD will receive many more smaller objects, > compared to the amount it would receive in a replicated setup. > > This must mean that the rocksdb will also need to handle this more > entries, and will grow faster. This will have an impact when using > bluestore for slow HDD with DB on SSD drives, where the faster growing > rocksdb might result in spillover to slow store - if not taken into > consideration when designing the disk layout. > > Are my thoughts on the right track or am I missing something? > > Has somebody done any measurement on rocksdb growth, comparing replica > vs EC ? > > If you want to be not affected on spillover of block.db - use 3/30/300 GB > partition for your block.db. > > > > k > > _______________________________________________ > ceph-users mailing > listceph-us...@lists.ceph.comhttp://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > > _______________________________________________ > ceph-users mailing list > ceph-users@lists.ceph.com > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com >
_______________________________________________ ceph-users mailing list ceph-users@lists.ceph.com http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
