Ben Clewett <B.Clewett@roadrunner.uk.com> writes:
> If I wanted to divide the postmaster read() calls evenly to files
> located over several physical disks, how would you suggest distributing
> the data-space?
AFAIK, the single biggest win you can get in this dimension is to put
the WAL log ($PGDATA/pg_xlog/) on a separate spindle from everything
else. At least for write-intensive databases, that can buy you
something like 2x improvement for the price of one easy symlink.
After that, the conventional wisdom is to put indexes on a third spindle
(separate from base tables and from xlog). But the bookkeeping and
maintenance effort needed for that is really too high to make it worth
worrying about, IMHO :-(. Eventually we will have some kind of
tablespace feature to make it easy.
My recommendation at the moment would be: WAL on dedicated spindle,
everything else on the best RAID array you can set up. And buy as much
RAM as you can afford.
See past discussions in pgsql-performance for more info.
regards, tom lane
