"Weber, Johann (ISS Kassel)" <jweber@iss.net> writes:
> Is this true for PostgreSQL (V 8.0 on ReadHat)? My tests do not show any
> speed gained when placing pg_clog and pg_xlog on a different drive.
The conventional wisdom is that it's a win to have pg_xlog on a drive by
itself. The above is not that. pg_clog is more in the nature of data,
and in any case you lose the advantage as soon as the drive handling
pg_xlog has to move the head away from the current xlog file.
Whether any particular test case would show an advantage is another
question of course. In a heavy-write scenario I would think you could
probably measure a win.
regards, tom lane