When is RAID-5 too large

[Victor Semaska_3]

Greetings,

It has been awhile since I had to set up a RAID-5 set since we're mainly using an EVA 3000 for storage. Anyway, the server is a DS25 with Smart Array 5304A running Tru64 V5.1B. There currently is a 5 disk RAID-5 set and we're going to buy another 5 disks.

Question is, is it better to rebuild the RAID-5 set as a 10 disk set or just set up another 5 disk RAID-5 set? Is there a threshold for RAID-5 sets that shouldn't be exceeded? The server is an Oracle database server for report generation so the I/O is mostly reads.

Thanks,
Vic

[Marek Nelec]

Hi

14 drives is the maximum recommended by HP for RAID-5 sets. I really don't know however what would be better for you: expanding the array, or creating a new RAID-5 set. If you expand the array you'll be able to use capacity of all the new drives. Performance-wise I think it would be better to connect the new drives to a second SCSI channel of the controller and create another RAID-5 (if possible) set.