SATA drives performance

Hi all,

I'm trying to figure out which HW configuration with 3 SATA drives is
the best in terms of reliability and performance for Postgres database.

I'm thinking to connect two drives in RAID 0, and to keep the database
(and WAL) on these disks - to improve the write performance of the SATA
drives.

The third drive will be used to reduce the cost of the RAID 0 failure
without reducing the performance. Say, I could configure Postgres to use
the third drive as backup for WAL files, with archive_timeout set to 15
minutes. Daily backups will be created on different server. Loss of last
15 minute updates is something the customer can afford. Also, one day
restore time is case of failure is also affordable (to reinstall the OS,
Postgres, restore backup, and load WALs).

The server will be remotely administered, that is why I'm not going for
RAID 1, 1+0 or some other solution for which, I beleive, the local
administion is crucial.

Server must be low budget, that is why I'm avoiding SAS drives. We will
use CentOS Linux and Postgres 8.4. The database will have 90% of read
actions, and 10% of writes.

I would like to hear your opinion, is this reasonable or I should
reconsider RAID 1?

Regards,
Ognjen