Re: 10K vs 15k rpm for analytics

On Tue, Mar 2, 2010 at 1:42 PM, Francisco Reyes <lists(at)stringsutils(dot)com> wrote:
> Anyone has any experience doing analytics with postgres. In particular if
> 10K rpm drives are good enough vs using 15K rpm, over 24 drives. Price
> difference is $3,000.
>
> Rarely ever have more than 2 or 3 connections to the machine.
>
> So far from what I have seen throughput is more important than TPS for the
> queries we do. Usually we end up doing sequential scans to do
> summaries/aggregates.

Then the real thing to compare is the speed of the drives for
throughput not rpm. Using older 15k drives would actually be slower
than some more modern 10k or even 7.2k drives.

Another issue would be whether or not to short stroke the drives. You
may find that short stroked 10k drives provide the same throughput for
much less money. The 10krpm 2.5" ultrastar C10K300 drives have a
throughput numbers of 143 to 88 Meg/sec, which is quite respectable,
and you can put 24 into a 2U supermicro case and save rack space too.
The 15k 2.5" ultrastar c15k147 drives are 159 to 116, only a bit
faster. And if short stroked the 10k drives should be competitive.