Oracle on Solaris: separate disks or concatenate?

We use a commercial application that is built on top of Oracle. When we initially purchased it the application's vendor configured a SunFire V880 with 4 of the 6 internal firewire disks as one concatenated volume. The other two are the system disk and a spare/scratch space disk. It's Solaris 8, Oracle is 9.0.1.

We are going to add another 200-300Gb of storage to this system, probably with a U320 SCSI adapter in the SunFire attached to some sort of rack mounted JBOD, using either direct SCSI to SCSI or maybe SCSI to SATA. What I'm trying to determine is, given that 100% of the data that will be held on this new storage will consist of Oracle files, is there any advantage, performance or otherwise, in making those disks into another md volume? Backups are via ufsdump on an idle system to a SuperDLT tape, supposedly 320Gb/cartridge. So making one huge md volume is not attractive since the ufsdump of that big volume won't fit on a single cartridge.

Our up time requirements are not stringent -we don't need the redundancy of a RAID configuration. I assume that sooner or later we will see disk failures on the SCSI attached storage, and everything else being equal, I don't see how restoring N ufsdumps one disk at a time from a single tape is going to differ very much from restoring 1 ufsdump that is N times bigger to the concatenated md volume from that same tape. However, I'm guessing that removing md might eliminate some overhead so that IO from oracle <-> disk could be slightly faster.

Thoughts and/or suggestions?

Thanks,

David Mathog
mathog_at_caltech.edu Received on Tue Oct 04 2005 - 15:48:21 CDT