Optimizing Drive performance on a New System

[Frank W. Peters]

We will soon be getting a Sun 4/390 with 56MB of RAM and 5 1GB IPI disk
drives. This will be our first experience with setting up a system that
has more than one disk drive at setup and configuration time. This system
will probably become heavily loaded rather quickly so I would like to give
it every performance advantage possible.  I'd like to ask your opinions on
a ddrive allocation issue.

In your opinion should the various OS-related partitions (root, usr, var,
swap and the like) be centralized on one of the drives or distributed
among all five?  I've heard people come down on both sides of this
question.

On one hand some feel that it is better to keep the critical on one
partition so that a failure in one of the other four doesn't lead to a
total system failure.

On the other hand (and this is the had I personally sit on) some feel that
distributing the heavy work among the various drives would enhance the
system performance and that the increased risk (if any) would be minimal
given the reliability of most drives (and we will have regular nightly
backups to recover from).

Any opinions?  If you had a system with five identical drives would you
distribute the system among them or put it all on one drive?  Would you
fully distribute them (one OS-related partition on each disk) or put most
partitions one one disk and one partition on a seperate drive?  Would you
expect distributing the partitions to result in a significant performance
improvement?  Are IPI disks genereally at least as reliable as common SCSI
and SMD disks?

Any comments are welcome.

Thanks
--Frank