Forgive my ignorance, but what should I consider when sizing the partition which houses the pg_xlog area? Are logs cleared out every once in awhile or do they continue to accumulate? Let's say your DB is around 4 GB, what should the log area size be, or does the size of the DB not matter, if not which factors should be considered?
Also, on a related note, would putting the pg_xlog onto a RAID-0 array improve performance much? Striping seems great for parallelizing seeks, and seeks are, if I recall, the main bottleneck for disks. But since the logs are written in a serial manner, there should be little to no seeking so performance gains wouldn't be all that much compared to dedicated single disk logs?
Now straying even further from the original subject... Would hardware vs software RAID 0 not make a difference in reality? Software striping incurs CPU and SCSI bandwith overhead. But in production CPU shouldn't in theory be more than around 50% or so, if so there's a capacity issue and you should consider upgrading CPU. And with most modern SCSI cards, bandwith is much greater than disk speed, so the extra overhead wouldn't make much difference. This might explain the popularity of Veritas.