Re: Hardware/OS recommendations for large databases (

Alan,

On 11/18/05 9:31 AM, "Alan Stange" <stange(at)rentec(dot)com> wrote:

> Here's the output from one iteration of iostat -k 60 while the box is
> doing a select count(1) on a 238GB table.
>
> avg-cpu: %user %nice %sys %iowait %idle
> 0.99 0.00 17.97 32.40 48.64
>
> Device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn
> sdd 345.95 130732.53 0.00 7843952 0
>
> We're reading 130MB/s for a full minute. About 20% of a single cpu was
> being used. The remainder being idle.

Cool - thanks for the results. Is that % of one CPU, or of 2? Was the
system otherwise idle?

> We've done nothing fancy and achieved results you claim shouldn't be
> possible. This is a system that was re-installed yesterday, no tuning
> was done to the file systems, kernel or storage array.

Are you happy with 130MB/s? How much did you pay for that? Is it more than
$2,000, or double my 2003 PC?

> What am I doing wrong?
>
> 9 years ago I co-designed a petabyte data store with a goal of 1GB/s IO
> (for a DOE lab). And now I don't know what I'm doing,

Cool. Would that be Sandia?

We routinely sustain 2,000 MB/s from disk on 16x 2003 era machines on
complex queries.

- Luke