Jon,
> Any help you can give in this would be extrememly helpful as I'm very
> far from an expert on Linux filesystems and postgres tuning.
See Tom's response; it may be that you don't have an issue at all.
If you do, it's probably the kernel, not the FS. 2.6.8 and a few other
2.6.single-digit kernels had memory leaks in shmem that would cause
gradually escalating swappage. The solution to that one is to upgrade to
2.6.11.
--
--Josh
Josh Berkus
Aglio Database Solutions
San Francisco