Hi Frank,
2018-03-04 1:40 GMT+01:00 Frank Ritchie <frankaritc...@gmail.com>: > Hi all, > > I have a few questions on using BlueStore. > > With FileStore it is not uncommon to see 1 nvme device being used as the > journal device for up to 12 OSDs. > > Can an adequately sized nvme device also be used as the wal/db device for > up to 12 OSDs? > > Well, you could ask yourself the question: What's the impact of losing those 12 OSD's at once when the nvme device fails? If the OSD's are slow spinners you probably won't have to worry about performance using the nmve device as wal/db. Are there any rules of thumb for sizing wal/db? > > As David Turner mentioned on a previous post, you would be ok with using around 10GB per TB of OSD. So 40GB wal/db partition for a 4TB OSD. This is no hard 'rule' to follow but will likely be enough to avoid spillover of the DB to the spinner disks. The actual size of the DB is depending on a few factors such as number of objects. Hope this helps, Caspar > Would love to hear some actual numbers from users. > > thx > Frank > > > > _______________________________________________ > ceph-users mailing list > ceph-users@lists.ceph.com > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > >
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