System Load analyze

Hi all,

i have a system here with 2 2.4GHz Xeon Processors, 2GB RAM, ONE Disk on
a Battery Backed Write Cache SCSI Controller and PostgreSQL 8.1.4
running with the data on a DRBD Device for High Availability. The used
database is also replicated to two similar machines with slony1.

Since the load average is between 1 (most of the time) and 10 (peeks) i
am worried about the load and executed vmstat and iostat which show that
1000-6000 Blocks are writen per second. Please check the attached output
for further details.
top shows that the CPUs are at least 80% idle most of the time so i
think there is an I/O bottleneck. I'm aware that this hardware setup is
probably not sufficient but is would like to investigate how critical
the situation is.

thanks,
Peter