need advice on filesystem layout

I am setting up a new HP K200 with a RAID array of 20 1 MB disks. After reading all the comments about lousy performance with RAID level 5, we've decided to use RAID level 1.

We will have at least 3 production databases on the system.

My boss has suggested striping the whole 20 MB into 20 file systems (meaning that each file system would be spread over all of the disks.)
I am afraid that if I do this, we will have lots of contention for the disks, since each file system will be on all the disks.

I've heard that it's a good idea to separate the data tablespaces, system tablespaces, indexes, rollback segments and redo logs, since they are all used at once in a transaction.

I am leaning toward setting up 5 files systems on small groups of disks maybe group 3 disks into 1 file system for the index tablespaces, another 2 disks into a 2MB file system for all the system tablespaces, another 3 disks into a file system for the redo logs, 1 disk for the rollback segments,
and the rest of the disks into 2 or 3 large files system for all the data tablespaces.

Has anyone tried either of these approaches? Would one of them work better than the other?  

Sue Brunkow
Brooktree Corp
San Diego, CA

brunkow_at_brooktree.com Received on Tue Oct 31 1995 - 00:00:00 CET