RAID 1: breaking mirrors and rebuilding drives, 4th Edition

Breaking a mirror and rebuilding the array using the

manual method

CAUTION

Use the following procedure for configurations with only one

array on the controller. If you configure multiple arrays on a

single controller, all arrays must be broken and restored

together. Because of the added complexity for multiple arrays,

we discourage this method of creating a backup of the logical

driver.

You can break a RAID 1 or RAID 1(+0) mirror simply by removing a drive while the server is online.

You must shut down the server first if you want to preserve the data on drives you are removing. If you

want to use the removed drives to restore the server, or if you need the data on the drives for any

other reason, follow these steps exactly to break a mirror:

1. Verify that the controller contains RAID 1 or RAID 1(+0) logical drives only.

2. Shut down the OS to ensure a clean file system shutdown.

3. Power off the server.

4. Remove one-half of the drives created by the mirror (the backup). Label each removed drive with

its respective drive bay number.

NOTE

For two-drive configurations, just remove one drive. For larger

RAID 1+0 configurations, the first n/2 drives are always mirrored

to the second n/2 drives (unless drives have been physically

reordered using Offline Drive Movement). Always remove the set

of drives that are one side of the mirrored array. Do not remove

drives from opposite sides of the mirror.

5. Restart the OS with the remaining half of the drives that the mirror created.

6. You will get a message during boot-up indicating that the removed drives are not responding

(Figure 1).

7. Press F2 to fail the missing drive(s) and continue in recovery mode. All drives on the controller will

remain disabled until you press F2. If you press F1 by mistake, simply reboot again and press F2

to fail the drives.

If you are breaking the mirror to test an OS patch, you should normally test the OS patch before

making the array fault-tolerant again. Using this approach, you can verify the OS patch before

beginning the rebuild in step 8 and replicating it across the mirror.