15.3.3 Failure in Multiple Logical Drives Simultaneously

If a disk drive fails in more than one logical drive at the same time (one failure per logical drive), and the logical drives have hot spares protecting them, the controller rebuilds the logical drives with these limitations:

A hot spare must be at least as big as the smallest disk drive in the array that it might replace.
Failed disk drives are replaced with hot spares in the order in which they failed. (The logical drive that includes the disk drive that failed first is rebuilt first, assuming an appropriate hot spare is available—see the previous bullet.)

Note: If the number of disk drive failures exceeds the number of hot spares, see Failed Disk Drive Not Protected by a Hot Spare..