has a capacity closest to and at least as great as that of the failed drive to take the place of the failed drive.

Note: Hot spares are used only in arrays with redundancy—for example, RAID levels 1, 5, 10, and 50. A hot spare connected to a specific MegaRAID SCSI 320-2 controller can be used only to rebuild a drive that is connected to the same controller.

2.3.10 Hot Swapping

Hot swapping is the manual replacement of a defective physical disk unit while the computer is still running. When a new drive has been installed, you must issue a command to rebuild the drive. The MegaRAID controller can be configured to detect the new disks and to rebuild the contents of the disk drive automatically.

2.3.11 Disk Rebuild

You rebuild a disk drive by recreating the data that had been stored on the drive before the drive failed. Rebuilding can be done only in arrays with data redundancy such as RAID level 1, 5, 10, and 50.

Standby (warm spare) rebuild is employed in a mirrored (RAID 1) system. If a disk drive fails, an identical drive is immediately available. The primary data source disk drive is the original disk drive.

A hot spare can be used to rebuild disk drives in RAID 1, 5, 10, or 50 systems. If a hot spare is not available, the failed disk drive must be replaced with a new disk drive so the data on the failed drive can be rebuilt.

The MegaRAID SCSI 320-2 controller automatically and transparently rebuilds failed drives with user-definable rebuild rates. If a hot spare is available, the rebuild starts automatically when a drive fails. MegaRAID SCSI 320-2 automatically restarts the system and the rebuild if the system goes down during a rebuild.

2.3.11.1Rebuild Rate

The rebuild rate is the fraction of the compute cycles dedicated to rebuilding failed drives. A rebuild rate of 100% means the system is

RAID Overview

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