On 04/24/2012 05:06 PM, Martin Mailand wrote: > Hi, > > Am 24.04.2012 17:23, schrieb João Eduardo Luís: >> Any chance you could run iotop during the busy periods and tell us which >> processes are issuing the io? > > sure, > http://85.214.49.87/ceph/iotop.txt > > -martin > I don't want to rush into a definite answer, but it looks like the IO bursts are caused by btrfs. The periods on which they happen are consistent with btrfs' internal thread scheduling (which are fired every 30 seconds), and from iotop it would seem as if they're the ones responsible for all the IO when it jumps from the "couple of MB/s" mark to "several hundreds of MB/s". I've seen it happen before, although on synthetic and very specific workloads. Not sure on what may be the cause in your case though. What kernel and btrfs versions are you using? -- João Eduardo Luís gpg key: 477C26E5 from pool.keyserver.eu
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