| From: | Josh Berkus <josh(at)agliodbs(dot)com> |
|---|---|
| To: | "scott(dot)marlowe" <scott(dot)marlowe(at)ihs(dot)com>, Chad Thompson <chad(at)weblinkservices(dot)com> |
| Cc: | pgsql-performance <pgsql-performance(at)postgresql(dot)org> |
| Subject: | Re: Looking for a cheap upgrade (RAID) |
| Date: | 2003-05-02 22:10:25 |
| Message-ID: | 200305021510.25982.josh@agliodbs.com |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-performance |
Scott,
> With that setup, you'd have 15 Gigs for the OS, 4 gigs for swap, and about
> 300 gigs for the database. The nice thing about RAID 5 is that random
> read performance for parallel load gets better as you add drives. Write
> performance gets a little better with more drives since it's likely that
> the drives you're writing to aren't the same ones being read.
Yeah, but I've found with relatively few drives (such as the minimum of 3)
that RAID 5 performance is considerably worse for writes than RAID 1 -- as
bad as 30-40% of the speed of a raw SCSI disk. This problem goes away with
more disks, of course.
--
-Josh Berkus
______AGLIO DATABASE SOLUTIONS___________________________
Josh Berkus
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