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What is drawer loss protection?

Drawer loss protection is an attribute of volume groups and disk pools. Drawer loss protection guarantees accessibility to the data on the volumes in a volume group or disk pool if a total loss of communication occurs with a single drawer in a drive tray. An example of total loss of communication might be failure of an internal component within the drawer.

Attention: Drawer loss protection is not guaranteed if a drive has already failed in the volume group or disk pool. In this situation, losing access to a drawer and consequently another drive in the volume group or disk pool causes loss of data.

Criteria for drawer loss protection

Level Criteria for Drawer Loss Protection Minimum number of drawers required
Disk Pool The disk pool includes drives from all five drawers and there are an equal number of drives in each drawer. A 60-drive tray can achieve Drawer Loss Protection when the disk pool contains 15, 20, 25, 30, 35, 40, 45, 50, 55, or 60 drives. 5
RAID 6 The volume group contains no more than two drives in a single drawer. 3
RAID 3 or RAID 5 Each drive in the volume group is located in a separate drawer. 3
RAID 1 Each drive in a mirrored pair must be located in a separate drawer. 2
RAID 0 Cannot achieve Drawer Loss Protection. Not applicable