You can use a for additional data protection from disk physical disk failures that occur in a , , , or . If the hot spare disk physical disk is available when a disk physical disk fails, the uses data to reconstruct the data from the failed disk physical disk to the hot spare disk physical disk. When you have physically replaced the failed disk physical disk, a operation occurs from the hot spare disk physical disk to the replaced disk physical disk. If you have designated the hot spare disk physical disk as a permanent member of a disk group, the copyback operation is not needed. Your stays online and accessible while you replace the failed disk physical disk, because the hot spare disk physical disk is automatically substituted for the failed disk physical disk.
Hot Spare Disk Physical Disk Capacity Considerations
Select a disk physical disk with a capacity equal to or greater than the total capacity of the disk physical disk that you want to make redundant with the hot spare. For example, if you have an 18-GB disk physical disk with configured capacity of 8 GB, you could use a 9-GB or larger disk physical disk as a hot spare. Generally, do not assign a disk physical disk as a hot spare unless its capacity is equal to or greater than the capacity of the largest disk physical disk on the storage array.
Note: If hot spares are not available that have the same physical capacity, then a disk physical disk with lower capacity may be used as a hot spare if the "used capacity" of the used disk physical disk is the same or smaller than the lower capacity hot spare.
How Many Hot Spare Disk Physical Disks Can You Create?
The maximum number of hot spare disk physical disks depends on the RAID controller module model, but the maximum is typically 15. You can have an unlimited number of global hot spare disk physical disks.