from the original members to larger drives, and then the smaller drives can be replaced without powering down the system.

Note on Expansion

1. Added Capacity:

When a new drive is added to an existing logical drive, the capacity brought by the new drive appears as a new partition. Assuming that you have 4 physical drives (each of the size of 36GB) in a logical drive, and that each drive’s miximum capacity is used, you will have a logical drive of the size of 108GB. One drive’s capacity is used for parity; e.g., RAID 3. A 36GB drive is added, the capacity will be increased to 144GB in two separate partitions (one is 108GB and the other 36GB).

2.Size of the New Drive:

A drive used for adding the capacity should have the same capacity as that of the array’s members.

3.Applicable Arrays:

Expansion can only be performed on RAID 0, 3, and 5 logical drives. Expansion can not be performed on a logical configurations that do not have parity; e.g., NRAID or RAID 1.

NOTE:

Expansion on RAID0 is not recommended, because the RAID0 array has no redundancy. Interruptions during the expansion process may cause unrecoverable data loss.

4.Interruption to the Process:

Expansion should not be canceled or interrupted once begun. A manual restart should be conducted after the occurrence of power failure or interruption of any kind.

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Compaq Infortrend manual Added Capacity