Alexander Staubo <alex(at)purefiction(dot)net> writes:
> I have a production PostgreSQL instance (8.1 on Linux 2.6.15) that
> seems to be writing data to disk at rates that I think are
> disproportional to the update load imposed on the database. I am
> looking for ways to determine the cause of this I/O.
Are you sure that iostat is to be trusted? The read numbers in
particular look suspiciously uniform ... it would be a strange
query load that would create a read demand changing less than 1%
from hour to hour, unless perhaps that represented the disk's
saturation point, which is not the case if you're not seeing
obvious performance problems.
regards, tom lane