Re: VACUUM degrades performance significantly. Database becomes unusable!

The system is actually idling when I ran the tests (load average: 0.01,
0.02, 0.00). When VACUUM runs, load average increases quickly (load average:
1.77, 0.60, 0.21) just by running psql on command line and issuing 2
queries. I've been running PostgreSQL for over 3 years now and IIRC VACUUM
has always been a show-stopper with or without the FULL attribute on my
system (from linux 2.2 to linux 2.4, and from PostgreSQL 7.1 to PostgreSQL
7.3). The only thing that didn't change is the IDE drive. The problem is not
unique to this system, I have 2 machines with the same configuration and
VACUUM slows down both databases considerably. Unfortunately, I prefer to
implement a system on cheap IDE disks a la Google because my database is
expected to hit terabytes and SCSI cost becomes prohibitive.

Is anyone else getting performance degradation with VACUUM on Linux? I'm
thinking maybe Linux has a bad scheduler and high IO latency that other OSes
(eg. FreeBSD) do not suffer from. Although, someone did tell me that Redhat
9.0 Linux 2.4.20-8 has parts of the low latency patch applied but I
certainly don't feel the improvement on PostgreSQL.