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Note that there appears to be a significant random access write penality when the disk write cache is enabled (hdparm -W1 /dev/foo).
Cluster
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Hard Disk Bandwidth August 2011 (rc01-rc60)
Putting this data up in case we plug our disks back in and want to see if performance has changed much over time.
Note 'rcXX-2' indicates the second disk. rc01-rc40 have a WD2503ABYX enterprise disk in the first slot and a desktop Seagate ST3500418AS in the second. rc41-rc60 have only WD disks (which is pretty obvious in the fans high graph).
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