A hot spare is a drive containing no data that acts as a standby in case a drive fails in a RAID 1, 3, or 5 logical drive. The hot spare drive adds another level of redundancy to your storage subsystem. If a drive fails in the storage subsystem, the hot spare is automatically substituted for the failed drive without requiring a physical swap. If the hot spare drive is available when a drive fails, the controller will use redundancy data to reconstruct the data from the failed drive to the hot spare drive. When you have physically replaced the failed drive, a copyback
A hot spare drive is not dedicated to a specific array but instead is global (can be used for any failed drive in the storage subsystem with the same or smaller capacity).
A Hot Spare Drive - Standby, represented by this icon in the Subsystem Management Window Physical View , is a drive that has been assigned as a hot spare but is currently not taking over for any failed drive.
A Hot Spare Drive - In Use, represented by this icon in the Subsystem Management Window Physical View , is a drive that has been assigned as a hot spare and is currently taking over for a failed drive.