Rebuilding a RAID 5 disk array, Degraded

3ware Escalade ATA RAID Controller Installation Guide

array is removed, unplugged or fails on read or write requests, the array is marked as DEGRADED and the drive is marked as Not In Use or is not displayed if no longer available. (see Figure 13 and Figure 14).

You can still read and write data from a degraded disk array, but the array will not be fault tolerant until it is rebuilt using the Rebuild feature, described in the 3ware Disk Array Configuration Utility or 3DM Disk Management Utility chapters.

			3ware Disk Array	Configuration
Available Drives:
Port 2	- QUANTUM FIREBALLP LM30			30.0GB
Port 3	- QUANTUM FIREBALLP LM30			30.0GB
Disk Arrays:
Array Unit			0 - 2 drive Mirror	30.0GB	DEGRADED
Port	0	-	QUANTUM FIREBALLP LM30	30.0GB	Not in Use
Port	1	-	QUANTUM FIREBALLP LM30	30.0GB

Create Array Delete Array Maintain Array Rebuild Array


Alt-F1 Help	Previous/Next $ Toggle Hot Spare EnterSelect/Deselect
F6 Restore Initial Values Esc Cancel		F8 Done

Figure 13. Degraded RAID 1 Array Drive When Not in Use

3ware Disk Array Configuration Utility

3ware Disk Array Configuration

Available Drives:
Disk Arrays:
Array Unit		0 - 4 drive 64K RAID 10	60.0GB	DEGRADED
Port 0	-	QUANTUM FIREBALLP LM30	30.0GB	Not in Use
Port 1	-	QUANTUM FIREBALLP LM30	30.0GB
Port 2	-	QUANTUM FIREBALLP LM30	30.0GB
Port 3	-	QUANTUM FIREBALLP LM30	30.0GB

Create Array Delete Array Maintain Array Rebuild Array


Alt-F1 Help	Previous/Next $ Toggle Hot Spare EnterSelect/Deselect
F6 Restore Initial Values Esc Cancel		F8 Done

Figure 14. Degraded RAID 10 Array Drive When Not in Use

Note: A RAID 10 array can be configured with either four, six, eight, ten or twelve drives. In a 4-drive config- uration, up to two drives can be rebuilt. In a 6-drive con- figuration, up to three drives can be rebuilt. In an 8-drive configuration, up to four drives can be rebuilt. In a 12- drive configuration, up to six drives can be rebuilt.

Rebuilding a RAID 5 disk array

Escalade ATA RAID Controllers allow you to create fault tolerant RAID 5 disk arrays. These disk arrays achieve fault tolerance by using a simple (exclusive OR) function to generate the parity data