On 5/28/14 07:19 , Cedric Lemarchand wrote: > Le 28/05/2014 16:15, Stefan Priebe - Profihost AG a ?crit : >> Am 28.05.2014 16:13, schrieb Wido den Hollander: >>> On 05/28/2014 04:11 PM, VELARTIS Philipp D?rhammer wrote: >>>> Is someone using btrfs in production? >>>> I know people say it?s still not stable. But do we use so many features >>>> with ceph? And facebook uses it also in production. Would be a big speed >>>> gain. >>> As far as I know the main problem is still performance degradation over >>> time. On a SSD-only cluster this would be less of a problem since seek >>> times on SSDs aren't a really big problem, but on spinning disks they are. >>> >>> I haven't seen btrfs in production on any Ceph cluster I encountered. >> It heavily fragements over time. > I just would add that it is inherent to *all* COW based file system, and > not specifically to BTRFS ;-) > > Cheers > > C?dric I agree, but it appears to affect BtrFS more than others. I'm using ZFS for other things (not Ceph). Those filesystems are slower after several years, but only by a few percent (estimating from RRD graphs). ZFS made a design decision to ignore fragmentation, as long as the zpool is less than 80% full. Once there, it switches to an optimal placement algorithm instead of the fast-but-inefficient placement algorithm. This drives up the CPU usage and kills the IOps. So it does suffer, but the pain doesn't hit until > 80% full. I don't recall VxFS having any issue when using COW, but it's been a while. The multi-million dollar storage array probably helped. I never used ReiserFS in production, so I can't comment. I haven't tried any other COW filesystems. -- *Craig Lewis* Senior Systems Engineer Office +1.714.602.1309 Email clewis at centraldesktop.com <mailto:clewis at centraldesktop.com> *Central Desktop. Work together in ways you never thought possible.* Connect with us Website <http://www.centraldesktop.com/> | Twitter <http://www.twitter.com/centraldesktop> | Facebook <http://www.facebook.com/CentralDesktop> | LinkedIn <http://www.linkedin.com/groups?gid=147417> | Blog <http://cdblog.centraldesktop.com/> -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.ceph.com/pipermail/ceph-users-ceph.com/attachments/20140528/2992e73d/attachment.htm>
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