reconfiguring diskspace while upgrading to 8.2.5

Admin team,

We are upgrading from Postgres 7.4.5 to 8.2.5 in mid January.  We are also adding new disks

As we go.  I am investigating using the new tablespace facility to move our biggest and most accessed

Table to the new disk.  Here are the statistics.  We are running RAID 10

  Current database size -------------   63 GIG

  Heavy accessed table to move:

           Table -----------------------   7.4 GIG

           2 indexes -------------------   3 GIG apiece

           2 other indexes -------------   2.5 GIG apiece

Current database disk configuration

          TOTAL space -------------- 404 GIG

           TOTAL spindles -----------      3

           TOTAL mirrors ------------      3

 New additional disk configuration

           TOTAL  space ------------   290 GIG

           TOTAL spindles -----------       2

           TOTAL mirrors   -----------      2

The choices we see are:

    1. Adding the two new spindles to the other three making one huge logical partition

        And all 350+ tables and 400+ indexes continue to reside there

    2. Keeping the two new spindles separate and dedicating the heavy access table

         And its 4 indexes to it.

    3. Keeping the two new spindles separate and dedicating the heavy access table

          To it, but keeping the 4 indexes on the old partition.

I know that maintaining almost 700 GIG of total disk space being utilized by a 63 GIG

  Database looks like disk-space overkill but we do expect massive growth over the

  Next 2 – 3 years.

Any thoughts / comments would be appreciated.

Also are there tools out there that monitor disk I/O and disk speed?

Thanks for your time,