Bluestore shouldn't have changed the disk requirements at all. I presume you are running a kernel newer than 2.6.33 so are probably okay with having the drive cache on, but it will vary with your controller I suspect. -Greg
On Mon, Oct 23, 2017, 3:32 AM Hans van den Bogert <[email protected]> wrote: > Hi All, > > For Jewel there is this page about drive cache: > http://docs.ceph.com/docs/jewel/rados/configuration/filesystem-recommendations/#hard-drive-prep > > For Bluestore I can't find any documentation or discussions about drive > write cache, while I can imagine that revisiting this subject might be > necessary. > > For our cluster specifically, we use HP gen 9 with a b140i controller > where disks are directly attached (i.e., not RAID). Often with the Linux > kernel, controllers automatically enable drive write cache for directly > attached harddisks since this *should* be safe as long as harddisks > correctly adhere to flush semantics . In the case of the b140i controller; > I can confirm with `hdparm -W /dev/sdx` that drive write cache is *not* > enabled by default. > > So my main two questions are: > > 1. Did anybody do extensive testing, with luminous in combination with > drive write cache enabled, or at least elaborate on the subject. > 2. Depending on item 1., could and should I enable drive write cache for > the disks attached to a HP b140i controller. > > Thanks! > > Hans > _______________________________________________ > ceph-users mailing list > [email protected] > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com >
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