Slow Write Performance on 3ware controller

[Nikolas Britton]

On 7/23/06, Nikolas Britton <nikolas.britton at gmail.com> wrote:
> On 7/22/06, Richard Collyer <richard at firebadger.net> wrote:
> > Completely ignore me. Write caching wasnt turned on.
> >
>
> Even with write caching off you should be able to hit 50MB/s... did I
> missing something? Try running 'diskinfo -t /dev/diskname'. For
> refrence here are the numbers from my single 400GB Seagate ST3400832AS
> drive, if you can't bet it then something is wrong with your setup:
>
> > diskinfo -t /dev/ad4
> /dev/ad4
>         512             # sectorsize
>         400088457216    # mediasize in bytes (373G)
>         781422768       # mediasize in sectors
>         775221          # Cylinders according to firmware.
>         16              # Heads according to firmware.
>         63              # Sectors according to firmware.
>
> Seek times:
>         Full stroke:      250 iter in   5.844998 sec =   23.380 msec
>         Half stroke:      250 iter in   4.558075 sec =   18.232 msec
>         Quarter stroke:   500 iter in   7.147166 sec =   14.294 msec
>         Short forward:    400 iter in   2.253667 sec =    5.634 msec
>         Short backward:   400 iter in   2.013481 sec =    5.034 msec
>         Seq outer:       2048 iter in   0.332809 sec =    0.163 msec
>         Seq inner:       2048 iter in   0.349674 sec =    0.171 msec
> Transfer rates:
>         outside:       102400 kbytes in   1.503943 sec =    68088 kbytes/sec
>         middle:        102400 kbytes in   1.688924 sec =    60630 kbytes/sec
>         inside:        102400 kbytes in   3.021035 sec =    33896 kbytes/sec
>

To test write speed use dd: 'dd if=/dev/zero of=testfile bs=4m'

^C128+0 records in
127+0 records out
532676608 bytes transferred in 10.840476 secs (49137752 bytes/sec) 46.87MB/s.


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