Thanks Janne! Chad. On 1/10/20 1:55 AM, Janne Johansson wrote: > Den tors 9 jan. 2020 kl 17:16 skrev Chad W Seys <cwseys@xxxxxxxxxxxxxxxx > <mailto:cwseys@xxxxxxxxxxxxxxxx>>: > > Hi all, > In the era of Mimic, what are best practices for setting up > cephfs on > a hard drive only cluster? > Our old cluster which began life in Emperor and has been upgraded > until now running Mimic. 21 hard drives ranging from 1 to 4 TB. (Yeah, > ceph doesn't like that.) It has a triply replicated cache tier in > front > of a k2m2 erasure coded pool. Our main usage these days is cephfs. > I vaguely remember a few ideas, which might be out of date or > never true: > Bluestore is slower than filestore on hard drives. ? > > > I guess one will have to measure with the specific hardware, but from > all the filestore->bluestore migration docs, it seems bluestore will > skip a lot of extra writes added by having filestore on top of another > filesystem (xfs mostly), so it should give more iops per OSD for writes > at least. Also, bluestore will need more manual tuning in terms of RAM, > since it (as said) doesn't talk normal filesystem so the "use all free > ram on OSD hosts for read caches" doesn't apply, but you can set per-OSD > memory cache size on bluestore to get more or less similar caching. > > Before release X replicated caches were needed to interface between > writers and the erasure coded pool, but after release X one could write > directly to the erasure coded pool. ? > > > There is still a penalty for making certain kinds of writes to EC, so > you might still want to have a replicated cache pool in front if it > works out for you now. > -- > May the most significant bit of your life be positive. _______________________________________________ ceph-users mailing list -- ceph-users@xxxxxxx To unsubscribe send an email to ceph-users-leave@xxxxxxx
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