improves upon RAID 6 performance. It also offers more protection than a single RAID level. Use RAID 60
when you need improved fault tolerance, high capacity and impressive write speeds.
A minimum of eight hard drives is required for a RAID 60 array. Since a RAID 60 array has a high number of
hard drives, the time to initialize and rebuild data is longer than a single RAID level.
RAID+Spare
A RAID+Spare array gives you a “hot-spare” that is ready to synchronize data immediately should a hard drive
fail. If a hard drive in the array fails, the data starts to synchronize with the spare. The advantage for a RAID
array with a spare is the immediacy of the replacement hard drive. However, the spare cannot be used as
storage during standard operation since its sole task is to take over should a hard drive fail.
You can replace the failed hard drive immediately and, once synchronization is complete, assign it as a new
spare.
Drive failures and synchronizing a spare hard drive
For RAID+Spare arrays, data remains intact when the minimum number of redundant hard drives fail.
However, if an additional hard drive fails before or during data synchronization with a spare hard drive, the
data in the array is lost. See the examples below.
RAIDs 1 and 5: one drive has failed and the array immediately begins to synchronize with the spare hard
drive. If a second hard drive in the RAID 5 array fails before synchronization is complete, all data in the
array is lost.
RAID 6: two hard drives have failed and the array immediately begins to synchronize the first failed hard
drive with the spare. If a third hard drive in the RAID 5 array fails before synchronization is complete, all
data in the array is lost.
Nested RAID: nested RAID levels have greater fault tolerances depending upon which of the nested RAID
arrays have hard drives that fail.
RAIDs 10 and 50: each of the nested arrays can can lose one hard drive. If one of the two nested
arrays loses two hard drives before or during the synchronization, data is lost.
