Dell MD3200, MD3220 Global Hot Spares, Hot Spare Operation, Hot Spare Drive Protection, 116

Ahot spare is an idle, powered-on, stand-by physical disk ready for immediate use in case of disk failure. If a hot spare is defined in an enclosure in which a redundant virtual disk experiences a physical disk failure, a rebuild of the degraded virtual disk is automatically initiated by the RAID controller modules. If no hot spares are defined, the rebuild process is initiated by the RAID controller modules when a replacement physical disk is inserted into the storage array.

Global Hot Spares

The MD3200 Series supports global hot spares. A global hot spare can replace a failed physical disk in any virtual disk with a redundant RAID level as long as the capacity of the hot spare is equal to or larger than the size of the configured capacity on the physical disk it replaces, including its metadata.

Hot Spare Operation

When a physical disk fails, the virtual disk automatically rebuilds using an available hot spare. When a replacement physical disk is installed, data from the hot spare is copied back to the replacement physical disk. This function is called copy back. By default, the RAID controller module automatically configures the number and type of hot spares based on the number and capacity of the physical disks in your system.

A hot spare may have the following states:

•Standby hot spare—is a physical disk that is assigned as a hot spare and is available to take over for any failed physical disk.

•In-use hot spare—is a physical disk that is assigned as a hot spare and is currently replacing a failed physical disk.

Hot Spare Drive Protection

You can use a hot spare physical disk for additional data protection from physical disk failures that occur in a RAID level 1, or RAID level 5 disk group. If the hot spare physical disk is available when a physical disk fails, the RAID controller module uses redundancy data to reconstruct the data from the failed physical disk to the hot spare physical disk. When you have physically replaced the failed physical disk, a copyback operation occurs from the hot spare physical disk to the replaced physical disk.

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Configuration: Disk Groups and Virtual Disks