Compaq 3000 manual Diagram of RAID 0+1 Write, RAID 0+1 Example

RAID Array 3000 Controller Shelf

Figure 2–7 Diagram of RAID 0+1 Write

Host Data	Controller divides		Striped data written
	the data into
			to half the drives
1110	chunksized units
1101
		1110
1011
		1101	Striped data mirrored
		1011
			to the remaining drives

SHR-1056

In the event of a drive failure, a RAID 0+1 array will enter degraded mode and continue to operate by substituting the failed drive with its mirror.

When the controller creates a RAID 0+1 set, it first sorts the drives by channel number and SCSI ID. Then it stripes the data across every other drive and forms a mirrored pair with the first two drives, another mirrored pair with the second two drives, and so on. Table 2–4 describes how the controller uses the drives in a RAID 0+1 set.

Table 2–4 RAID 0+1 Example

Drives Selected

Channel 1, ID 0

Channel 1, ID 1

Channel 1, ID 2

Channel 2, ID 0

Channel 2, ID 1

Channel 2, ID 2

Function

First member of stripe set.

Mirror of channel 1, ID 0

Second member of stripe set

Mirror of channel 1, ID 2

Third member of stripe set

Mirror of channel 2, ID 1

2–12 EK–SMCPQ–UG. C01