XFS vs Ext3, and schedulers, for WAL

All,

There's a number of blog tests floating around comparing XFS and Ext3,
and the various Linux schedulers, for PGDATA or for an all-in-one mount.

However, the WAL has a rather particular write pattern, and it's
reasonable to assume that it shouldn't be optimized the same way as
PGDATA.  Has anyone done any head-to-heads for WAL drive configuration
changes?

--
                                  -- Josh Berkus
                                     PostgreSQL Experts Inc.
                                     http://www.pgexperts.com