RE: Kenwood/Hi-Val True-X 40x CDROM drive.

BROWN Nick (Nick.BROWN@coe.int)
Tue, 4 May 1999 09:59:50 +0200


>The results of hdparm are often a bit misleading. I've got two IDE
disks
>hooked up in a RAID0 (striping) configuration. hdparm reports 14
mb/sec
>for the separate disks, but 2.6 mb/sec for the RAID array. When I
test
>it by writing and reading a few 1 gb datafiles, the speed is about
21
>mb/sec. Quite a difference, 2.6 or 21 mb/sec...

I've given up on hdparm. With my generic IDE disk, I get 8 MB/sec, and
about 22 MB/sec if I read from the cache. With my 7200 rpm SCSI disks (OK,
SCSI-2, not SCSI-3, but still...), I get between 1.8 and 3.5 MB/sec
(depending on wind direction, it seems) reading the disk, and 25 to 33
MB/sec reading the cache (which presumably means it's not the controller
being slower than IDE).

Meanwhile my own informal benchmarks (copy from /dev/xdx to /dev/null) show
the SCSI disks to be slightly faster than the IDE disk, which seems
reasonable. Are the hdparm numbers from the same school of thought that
gave us bogoMIPs ?

Nick Brown, Strasbourg, France (Nick(dot)Brown(at)coe(dot)int)

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