Re: tuning disk on 3ware /performance problem

[dean gaudet]

On Sun, 6 Apr 2003, Chuck Ebbert wrote:

>
>
>
> > Is there anything i can do to tune the drives connected to he 3ware
> > controller ? (37MB/sec vs 43MB/sec) (and why is the seq. output block
> > 65MB/sec on the 3ware vs 41MB/sec on 'ide controllers')
>
>
> Try doing a real test with a 1 GB file on an empty filesystem:
>
>
> # mount /fs && date
> # time dd if=/dev/zero of=/fs/file1 bs=128k count=8k

that should be:

time 'dd if=/dev/zero of=/fs/file1 bs=128k count=8k && sync'

otherwise you're not measuring the time it takes to get all the data to
disk.

or use lmdd from lmbench, and its built in syncing options.

> # umount /fs && date && mount /fs

or i suppose if you're not looking at the output of "time" and rather hand
subtracting the two dates?

-dean

> # time dd if=/fs/file1 of=/dev/null bs=128k
>
>
> I get numbers that disagree with hdparm by a large amount.
>
> --
>  Chuck
>  I am not a number!
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