The ~4% recommendation in the docs is missleading. How much you need really depends on how you use it, for CephFS that means: are you going to put lots of small files on it? Or mainly big files? If you expect lots of small files: go for a DB that's > ~300 GB. For mostly large files you are probably fine with a 60 GB DB.
As pointed out by others: 266 GB is the same as 60 GB. I expect the new Nautilus warning for spillover to bite a lot of people who didn't know about the undocumented magic numbers for sizes ;) Paul -- Paul Emmerich Looking for help with your Ceph cluster? Contact us at https://croit.io croit GmbH Freseniusstr. 31h 81247 München www.croit.io Tel: +49 89 1896585 90 On Tue, May 28, 2019 at 3:13 PM Jake Grimmett <j...@mrc-lmb.cam.ac.uk> wrote: > Dear All, > > Quick question regarding SSD sizing for a DB/WAL... > > I understand 4% is generally recommended for a DB/WAL. > > Does this 4% continue for "large" 12TB drives, or can we economise and > use a smaller DB/WAL? > > Ideally I'd fit a smaller drive providing a 266GB DB/WAL per 12TB OSD, > rather than 480GB. i.e. 2.2% rather than 4%. > > Will "bad things" happen as the OSD fills with a smaller DB/WAL? > > By the way the cluster will mainly be providing CephFS, fairly large > files, and will use erasure encoding. > > many thanks for any advice, > > Jake > > > _______________________________________________ > ceph-users mailing list > ceph-users@lists.ceph.com > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com >
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