Best Posgres tuning seettings for rendering

Hi,

I’m running my own mod_tile server with a quite big OSM database (30GBs) on a 6 GB-RAM computer. The computer is a Ubuntu 10.04 mashine with a Postgres 8.4 database. I found some hints for importing, but not for rendering.

What settings for the postgres.conf would you recommend for my use case?

I did the following settings:
shared_buffers=3072MB
work_mem=722MB
maintenance_work_mem=722MB
autovacuum = off

My tests with on-demand rendering didn’t present for me a clear result on playing with that values. I’m not sure if work_mem should be less or more and if maintenance_work_mem could have a negative effect, because I’m not updating or importing new OSM data. Rendering with browser window is acceptable until from zoom level 18 to 16, but its getting slower and slower from 15 to smaller scales.

Some advices?

Hi,

I`m interested how to best optimize the server performance too.

thanks,
Nikolay