Hello, On Sun, 21 Sep 2014 21:00:48 +0200 Udo Lembke wrote: > Hi Christian, > > On 21.09.2014 07:18, Christian Balzer wrote: > > ... > > Personally I found ext4 to be faster than XFS in nearly all use cases > > and the lack of full, real kernel integration of ZFS is something that > > doesn't appeal to me either. > a little bit OT... what kind of ext4-mount options do you use? > I have an 5-node cluster with xfs (60 osds), and perhaps the performance > with ext4 would be better?! Hard to tell w/o testing your particular load, I/O patterns. When benchmarking directly with single disks or RAIDs it is fairly straightforward to see: http://lists.ceph.com/pipermail/ceph-users-ceph.com/2014-April/028540.html Also note that the actual question has never been answered by the Ceph team, which is a shame as I venture that it would make things faster. Now testing with Ceph on top makes things a lot more murky, as Ceph currently is so inefficient (see the various OSD on SSD performance threads) that the underlying FS only makes a difference in certain scenarios. In the next few weeks I will probably have the chance to play with a cluster before it goes into production and refine those findings. I found that ext4 definitely fragments less than XFS (using RBD for VM images only here) over long term use. Nothing particular for mount options, but the biggest performance boost for ext4 is to give it the largest journal possible (-J size=1024) at mkfs time. > For xfs I use osd_mount_options_xfs = > "rw,noatime,inode64,logbsize=256k,delaylog,allocsize=4M" > That looks pretty much like the optimum settings for XFS indeed. Christian -- Christian Balzer Network/Systems Engineer chibi at gol.com Global OnLine Japan/Fusion Communications http://www.gol.com/
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