Tunning postgresql

Hello list,

I have 7.3.4 on RH 8, server hardware is a dual processor Intel Xeon 2.4
Ghz, 2G RAM. I was reading about tunning and would like to get some help
from you, I changed some of the default values and the performance
increased a little but I think still I can get more from that box.

What should be the right values to set in kernel and postgresql.conf to
get maximum performance, actually kernel share memory is:
cat /proc/sys/kernel/shmmax
268435456
cat /proc/sys/kernel/shmall
268435456

postgresql.conf contains these configurations modified:

shared_buffers = 17000 # min max_connections*2 or 16, 8KB each
max_fsm_relations = 400 # min 10, fsm is free space map, ~40
max_fsm_pages = 80000 # min 1000, fsm is free space map, ~6
max_locks_per_transaction = 64 # min 10
sort_mem = 16384 # min 64, size in KB
effective_cache_size = 1700000 # typically 8KB each

Still don't understand very well how to combine these parameters to gain
maximun performance for postgresql, any help or comment about this
would be very appreciated.

Thanks,

--
Josué Maldonado.