Hi Jake, I would definitely go for the "leave the rest unused" solution. Regards, Mattia On 5/29/19 4:25 PM, Jake ` wrote: > 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 > -- Mattia Belluco S3IT Services and Support for Science IT Office Y11 F 52 University of Zürich Winterthurerstrasse 190, CH-8057 Zürich (Switzerland) Tel: +41 44 635 42 22 _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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