Raid 5 Array with Different Sized Disks
 

Currently, we have a server with 3 18 gig SCSI drives set up in a Raid-5 configuration. Recently, one of the drives failed and we started searching for a spare. It turns out that 36GB drives are actaully cheaper than the 18GB drives the system already has, so I have a few questions.

1) I understand that RAID arrays can be made with disks of different sizes. Would we be able to just plug in a 36GB drive where the 18GB drive was and have it sync up and go, or would we need to remove the array and re-configure it?

2) Eventually, we hope to upgrade all three disks to 36GB drives. If the system sits in a mixed drive size configuration for a while, and then the rest of the drives are upgraded to 36GB drives, would we be able to increase the size of the RAID to use all the disk space on all three drives, or would we once again have to destroy the array and re-configure?

Thanks in advance for your help
-Dewar

1) I understand that RAID arrays can be made with disks of different sizes. Would we be able to just plug in a 36GB drive where the 18GB drive was and have it sync up and go, or would we need to remove the array and re-configure it?

...generally speaking, you can plug in a bigger disk and rebuild it into the array, however, keep in mind that you'll have 18GB of unusable disk space left over

2) 2) Eventually, we hope to upgrade all three disks to 36GB drives. If the system sits in a mixed drive size configuration for a while, and then the rest of the drives are upgraded to 36GB drives, would we be able to increase the size of the RAID to use all the disk space on all three drives, or would we once again have to destroy the array and re-configure?

...to take full advantage of the larger disks in the raid array, it's safer and easier to back up the data, blow away the array and build a new one with your 36gb disks.