Using hot spare disks

Hot spare disks are used to automatically replace a disk that has failed in a redundant RAID environment. For disk arrays with Easy Tier® function, it is important to note that a hot spare disk will only replace a disk in the tier that has the similar performance characteristics as the hot spare. Therefore, you need different hot spare disks available to fully cover all tiers in a tiered RAID level. For example, an SSD hot spare and a HDD hot spare.

Hot spare disks are useful only if their capacity is greater than or equal to that of the smallest capacity disk in an array that becomes degraded.