Thank you for a lot of detailed and useful information :) I'm tempted to ask a related question on SSD endurance... If 60GB is the sweet spot for each DB/WAL partition, and the SSD has spare capacity, for example, I'd budgeted 266GB per DB/WAL. Would it then be better to make a 60GB "sweet spot" sized DB/WALs, and leave the remaining SSD unused, as this would maximise the lifespan of the SSD, and speedup garbage collection? many thanks Jake On 5/29/19 9:56 AM, Mattia Belluco wrote: > On 5/29/19 5:40 AM, Konstantin Shalygin wrote: >> block.db should be 30Gb or 300Gb - anything between is pointless. There >> is described why: >> http://lists.ceph.com/pipermail/ceph-users-ceph.com/2019-February/033286.html > > Following some discussions we had at the past Cephalocon I beg to differ > on this point: when RocksDB needs to compact a layer it rewrites it > *before* deleting the old data; if you'd like to be sure you db does not > spill over to the spindle you should allocate twice the size of the > biggest layer to allow for compaction. I guess ~60 GB would be the sweet > spot assuming you don't plan to mess with size and multiplier of the > rocksDB layers and don't want to go all the way to 600 GB (300 GB x2) > > regards, > Mattia > > > _______________________________________________ > 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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