Andrew,
> None of this is to say that jfs is in fact to blame, nor even that,
> if it is, it does not have something to do with the age of our
> installations, &c. (these are all RH 8). In fact, I suspect hardware
> in both cases. But I thought I'd mention it just in case other
> people are seeing strange behaviour, on the principle of "better
> safe than sorry."
Always useful. Actually, I just fielded on IRC a report of poor I/O
utilization with XFS during checkpointing. Not sure if the problem is XFS
or PostgreSQL, but the fact that XFS (alone among filesystems) does its own
cache management instead of using the kernel cache makes me suspicious.
--
-Josh Berkus
Aglio Database Solutions
San Francisco