Re: opinion on disk speed

> -----Original Message-----
> From: pgsql-performance-owner(at)postgresql(dot)org
> [mailto:pgsql-performance-owner(at)postgresql(dot)org] On Behalf Of
> Vivek Khera
> Sent: 08 December 2005 16:52
> To: Postgresql Performance
> Subject: [PERFORM] opinion on disk speed
>
> I have a choice to make on a RAID enclosure:
>
> 14x 36GB 15kRPM ultra 320 SCSI drives
>
> OR
>
> 12x 72GB 10kRPM ultra 320 SCSI drives
>
> both would be configured into RAID 10 over two SCSI channels using a
> megaraid 320-2x card.
>
> My goal is speed. Either would provide more disk space than I would
> need over the next two years.
>
> The database does a good number of write transactions, and a decent
> number of sequential scans over the whole DB (about 60GB including
> indexes) for large reports.
>
> My only concern is the 10kRPM vs 15kRPM. The advantage of the 10k
> disks is that it would come from the same vendor as the systems to
> which it will be connected, making procurement easier.

15K drives (well, the Seagate Cheetah X15's that I have a lot of at
least) can run very hot compared to the 10K's. Might be worth bearing
(no pun intended) in mind.

Other than that, without knowing the full specs of the drives, you've
got 2 extra spindles and a probably-lower-seek time if you go for the
X15's so that would seem likely to be the faster option.

Regards, Dave