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I have a question about the Spare Drive on an HP ProLiant Raid Disk Array.

Does the Spare Drive have to be greater or equal the size of the largest RAID drive?

For example (is this configuration possible?):

Drive Bay 1 = 600 GB = RAID 5
Drive Bay 2 = 600 GB = RAID 5
Drive Bay 3 = 450 GB = RAID 5
Drive Bay 4 = 450 GB = RAID 5
Drive Bay 5 = 450 GB = RAID 5
Drive Bay 6 = 450 GB = Spare Drive on Standby

Thanks!

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2 Answers 2

up vote 5 down vote accepted

If the disks are part of the same array, the smallest disks would dictate the size used on the larger disks. That being the case, the 600GB would be utilized as 450GB.

Generally speaking, it's not advised to run different types of disks in the same array.

Depending on how fickle your controller is, it may not handle the mismatched disks. However, most modern controllers are tolerant of this.

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1  
+1, If he's using a HP SmartArray P or E series it will work exactly as described here. It is also specifically advised against by HP. –  Chris S Jul 15 '10 at 19:25

Drive Bay 1 = 600 GB = RAID 5
Drive Bay 2 = 600 GB = RAID 5
Drive Bay 3 = 450 GB = RAID 5
Drive Bay 4 = 450 GB = RAID 5
Drive Bay 5 = 450 GB = RAID 5
Drive Bay 6 = 450 GB = Spare Drive on Standby

Should be possible but your usable space will be 450 * 5 - 450 (parity) = 1800GB and not (600*2) + (450 *3) - 450 (parity) = 2100GB because the RAID array can only use smallest drive.

Now just because it should be possible doesn't mean I would run it that way.

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