On Mon, Feb 25, 2013 at 10:01:53AM -0600, Brian Cain wrote: > All, > > I have been observing some odd behavior regarding write throughput to an > XFS partition (the baseline kernel version is 2.6.32.27). I see > consistently high write throughput (close to the performance of the raw > block device) to the filesystem immediately after a mkfs, but after a few > test cycles, there is sporadic poor performance. > > The test mechanism is like so: > > [mkfs.xfs <blockdev>] (no flags/options, xfsprogs ver 3.1.1-0.1.36) > ... > 1. remove a previous test cycle's directory > 2. create a new directory > 3. open/write/close a small file (4kb) in this directory > 4. open/read/close this same small file (by the local NFS server) > 5. open[O_DIRECT]/write/write/write/.../close a large file (anywhere from > ~100MB to 200GB) > > Step #5 contains the high-throughput metrics which becomes an order of > magnitude worse several test cycles after a mkfs. Omitting steps 1-3 does > not show the poor performance behavior. > > Can anyone provide any suggestions as to an explanation for the behavior or > a way to mitigate it? Running xfs_fsr didn't seem to improve the results. > > I'm happy to share benchmarks, specific results data, or describe the > hardware being used for the measurements if it's helpful. Post your benchmark script, along with the results you see, and all the other information listed here: http://xfs.org/index.php/XFS_FAQ#Q:_What_information_should_I_include_when_reporting_a_problem.3F Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
