On Thu, 5 May 2011 00:08:59 +0100 Liam Kurmos <quantum.leaf@xxxxxxxxx> wrote: > in my tests i read 1GB and throw away the data. > dd if=/dev/md0 of=/dev/null bs=1M count=1000 If you have enough RAM for disk cache, on the second and further consecutive invocations of this you will be reading mostly from the cache, giving you an incorrect inflated result. So either don't forget to drop filesystem caches between runs, or just test read performance with "hdparm -t /dev/mdX" instead. -- With respect, Roman
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