I don't think that it makes sense to look at PG tuning and server
tuning as two separate tasks. XFS was recently benchmarked using
bonnie++ by Greg Smith, with interesting results:
http://blog.2ndquadrant.com/en/2010/04/the-return-of-xfs-on-linux.html
That said, my guess is that the majority of large Linux installations
are using ext3 or ext4. It isn't the case that there's a favoured
filesystem for Postgres.
The kernel parameters that you'll want to change are sysV IPC parameters:
http://www.postgresql.org/docs/current/static/kernel-resources.html
If you want a guide to choosing hardware for Postgres, I can highly
recommend Greg Smith's new book, "Postgresql 9 High performance".
--
Regards,
Peter Geoghegan
