Help specifying new machine

I'm thinking of upgrading an existing dedicated server and colocating my
own server.

The server is used for prototype systems running Postgresql, php and
apache. The largest database is presently under 10GB and I haven't had
any major performance problems. We expect to have to host larger data
sets in the next year and anticipate one or two databases reaching the
30GB mark in size. We write a lot of our webapps functionality using
pl/pgsql.

The present server is a 2GHz Pentium 4/512 KB cache with 2
software-raided ide disks (Maxtors) and 1GB of RAM.

I have been offered the following 1U server which I can just about
afford:

1U server
Intel Xeon 2.8GHz 512K cache 1
512MB PC2100 DDR ECC Registered 2
80Gb SATA HDD 4
4 port SATA card, 3 ware 8506-4 1
3 year next-day hardware warranty 1

There is an option for dual CPUs.

I intend to install the system (Debian testing) on the first disk and
run the other 3 disks under RAID5 and ext3.

I'm fairly ignorant about the issues relating to SATA vs SCSI and what
the best sort of RAM is for ensuring good database performance. I don't
require anything spectacular, just good speedy general performance.

I imagine dedicating around 25% of RAM to Shared Memory and 2-4% for
Sort memory.

Comments and advice gratefully received.
Rory

--
Rory Campbell-Lange
<rory(at)campbell-lange(dot)net>
<www.campbell-lange.net>