> -----Original Message-----
> From: pgsql-performance-owner@postgresql.org
> [mailto:pgsql-performance-owner@postgresql.org]
> On Behalf Of Ron Johnson
> Sent: Tuesday, October 29, 2002 3:10 PM
> To: pgsql-performance@postgresql.org
> Subject: Re: [pgsql-performance] Low Budget Performance
>
>
> On Tue, 2002-10-29 at 11:31, Andrew Sullivan wrote:
> > On Tue, Oct 29, 2002 at 09:10:31AM -0800, Josh Berkus
> > wrote:
> > >
> > > Out of curiousity, what is it with RAID 5? I've
> > > encountered the poor write performance too ... any
> > > idea why?
> >
> > It largely depends on the controller and the
> > implementation. It has to do with the cost of
> > calculating the checksum. If the implementation of
> > that is inefficient, the writes become inefficient.
>
> A high-quality smart controller with lots of cache RAM
> definitely negates the RAID5 performance issues.
>
> (Of course, I'm referring to enterprise-level rack-mounted
> h/w that costs big bucks...)
Only if you buy it new. EBay has some great deals these days. My company
just purchased a very nice Quad Xeon w/ 2GB RAM and last year's high-end
PERC RAID controller for under $5K. The external drive array was a bit more
expensive but that is an optional purchase. The 3x9GB SCSI drives that came
with the machine should be more than sufficient to run a greater than small
database server. If you don't want to spend $5K there are Dual Xeon machines
with less RAM and not quite so nice RAID controllers that you can get in the
$2.5K to $3.5K range.
rjsjr