I currently have a 9i database on a dual Xeon machine with 4GB RAM. There are only two 10k rpm disks on a U320 SCSI controller (which provides RAID 0 or RAID 1 only). The two disks are set up in a RAID 1 which stores OS, Oracle_Home, and all data files. I have room to add 4 more disks. Now, I'm trying to decide how to use the additional disks. Iniitally, I'm thinking make two more RAID 1 sets. Keep OS and Oracle software on the existing set, move data files to the second set, and indexes to the third.

Any advice on where to put redo, undo, temporary tablspace, and other data? I'm sure there are objective metrics to help me make this decision, any advice on where to find this info?

Thanks!
-MT