Online Contraction vs Offline Contraction
The Transparent RAID platform is extremely powerful in that almost all operations can be executed while the array is either online or offline. However, RAID Contraction is the exception and can only be executed in Offline mode.
Contracting an array (removing an existing data drive from an existing array)
1. RAID Contraction is supported in Offline mode only. So first, ensure that the array is offline.
If you attempt RAID Contraction in Online mode, you will be shown a message as shown below.
2. Select the disk to remove and click on the “Remove” toolbar button.
You have to option of specifying a Log RAID (recommended).
3. If you don’t specify a Log RAID, you will be warned as shown below.
4. The UI will update after the RAID Contraction operation completes.
It is a good idea to run the Verify+ operation on the array after completing the RAID Contraction.