SATA Raid (stress test..)

Nikolas Britton nikolas.britton at gmail.com
Thu Mar 2 06:41:40 PST 2006


On 3/2/06, Alex Zbyslaw <xfb52 at dial.pipex.com> wrote:
>
[snipped]
>
> Why not happy?  Transfer rates from 53 to 92Mb/s, give or take; what's
> wrong with that?  On a plain sata disk I get:
>
> Seek times:
>         Full stroke:      250 iter in   4.717248 sec =   18.869 msec
>         Half stroke:      250 iter in   5.342099 sec =   21.368 msec
>         Quarter stroke:   500 iter in   8.870424 sec =   17.741 msec
>         Short forward:    400 iter in   2.753187 sec =    6.883 msec
>         Short backward:   400 iter in   1.390941 sec =    3.477 msec
>         Seq outer:       2048 iter in   0.426796 sec =    0.208 msec
>         Seq inner:       2048 iter in   0.487280 sec =    0.238 msec
> Transfer rates:
>         outside:       102400 kbytes in   1.652736 sec =    61958 kbytes/sec
>         middle:        102400 kbytes in   1.697364 sec =    60329 kbytes/sec
>         inside:        102400 kbytes in   1.834759 sec =    55811 kbytes/sec
>
> A second, different, disk gives me better seek times but roughly similar
> transfer rates.  So I beat your inside transfer rate, but you're 50% up
> on the outside rate.
>
> If you have windows anywhere, then download sandra-lite.  Among other
> things, it has comparison benchmarks for all its tests, including disk
> transfer rates for things like SCSI-RAID0, RAID1, SATA/PATA-RAID0/1 etc.
>

diskinfo -t /dev/da0e
/dev/da0
        512             # sectorsize
        1756440297472   # mediasize in bytes (1.6T)
        3430547456      # mediasize in sectors
        213541          # Cylinders according to firmware.
        255             # Heads according to firmware.
        63              # Sectors according to firmware.

Seek times:
        Full stroke:      250 iter in   3.502539 sec =   14.010 msec
        Half stroke:      250 iter in   2.749807 sec =   10.999 msec
        Quarter stroke:   500 iter in   4.919431 sec =    9.839 msec
        Short forward:    400 iter in   2.257898 sec =    5.645 msec
        Short backward:   400 iter in   2.293915 sec =    5.735 msec
        Seq outer:       2048 iter in   0.132233 sec =    0.065 msec
        Seq inner:       2048 iter in   0.152473 sec =    0.074 msec
Transfer rates:
        outside:       102400 kbytes in   1.487112 sec =    68858 kbytes/sec
        middle:        102400 kbytes in   1.505039 sec =    68038 kbytes/sec
        inside:        102400 kbytes in   1.336495 sec =    76618 kbytes/sec


This and all the other benchmarks you've run are useless. Run a real
benchmark like iozone. It's in ports under benchmarks/iozone.
http://www.iozone.org/



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