Performance Tuning

Hello,

Can anyone help me with some performance tuning questions...

I have a new dedicated postgresql machine running red hat 7.2 with
postgresql 7.1.3.

The machine is a compaq with dual 1 ghz cpu's, 2gb ram 3 10k ultra3 sci
disks with a compaq raid5 controler. The filesystem is ext3.

There is one database about 6gb in size on the filesystem, with a total of
247 tables, ranging in size from small to approx 10 million rows.

What are some suggested values for the postgresql.conf file to take full
advantage of the system resources?

Here is what I'm using so far:

# Performance
#
#sort_mem = 512
sort_mem = 131072
#shared_buffers = 2*max_connections # min 16
shared_buffers = 65536
#fsync = true

Everything else is at defaults, since I really don't know what are
reasonable values for the optimizing stuff...

What about the wal_buffers...Should they be increased from 8? If so to
what?

The reason I ask is because this server is significantly more powerful
than the previous one and I'm not really seeing much performance gain and
actually experiencing some performance loss compared with the postgresql
7.0.2 installation on a shared web, app, database, mail, dns server... I
suspect some of it is due to enabling logging and tcp connections between
the DMZ and MZ, rather than the local domain socket, but I think this new
server could do better...

Any help is appreciated.

Regards,

Trevor Astrope
astrope(at)e-corp(dot)net