Priorities - PostgreSQL Wiki
http://wiki.postgresql.org/wiki/Priorities#Prioritizing_I.2FO some info about managing/prioritizing resources (CPU/IO/RAM) under PostgreSQL from the project’s WIKI
IO
CFQ - Wikipedia, the free encyclopedia
http://en.wikipedia.org/wiki/CFQ notes about Linux IO Scheduler - CFQ [Completely Fair Queue] . Also see http://en.wikipedia.org/wiki/Noop_scheduler http://en.wikipedia.org/wiki/Anticipatory_scheduling http://en.wikipedia.org/wiki/Deadline_scheduler
[Linux Journal, 2004] Kernel Korner - I/O Schedulers
http://www.linuxjournal.com/article/6931 Kernel Korner - I/O Schedulers
Peter Eisentraut's Blog: Solid-State Drive Benchmarks and the Write Cache
http://petereisentraut.blogspot.com/2009/07/solid-state-drive-benchmarks-and-write.html read this before rushing to by some SSDs
Graphing Linux Disk I/O statistics with Munin - Michael Renner's macro-blog
http://blogs.amd.co.at/robe/2008/12/graphing-linux-disk-io-statistics-with-munin.html tells you about a plugin (a perl script ) for munin that will collect linux disk IO stats and send it to munin for pretty graphs.
Optimizing Linux for random I/O on hardware RAID - Fishpool
http://www.fishpool.org/post/2008/03/31/Optimizing-Linux-I/O-on-hardware-RAID explains use linux IO scheulers with presence of smart RAID controllers.