On 01/28/2005-05:57PM, Alex Turner wrote:
> >
> > Your system A has the absolute worst case Raid 5, 3 drives. The more
> > drives you add to Raid 5 the better it gets but it will never beat Raid
> > 10. On top of it being the worst case, pg_xlog is not on a separate
> > spindle.
> >
>
> True for writes, but not for reads.
>
Good point.
>
> My main point is that you can spend $7k on a server and believe you
> have a fast system. The person who bought the original system was
> under the delusion that it would make a good DB server. For the same
> $7k a different configuration can yield a vastly different performance
> output. This means that it's not quite apples to snow shovels.
That point is definatly made. I primarily wanted to point out that the
controlers involved were not the only difference.
In my experience with SQL servers of various flavors fast disks and
getting things onto a separate spindles is more important than just
about anything else. Depending on the size of your 'hot' dataset
RAM could be more important and CPU never is.