13.1. Advantages of HP Smart Array Controllers

As data storage requirements increase and computing needs change, flexibility within server configurations and in storage configurations becomes more important. The HP Smart Array controller family includes a standard toolset that you can use to configure array controllers, expand an existing array configuration by adding disk drives, or reconfigure an array by extending volume sizes.

Only select Smart Array controllers offer RAID advanced data guarding (ADG), which offers higher fault tolerance than RAID 5 with lower implementation costs than RAID 1+0 and greater usable capacity per U than RAID 1. Using patented HP technology, you can safely deploy large-capacity disk drives and create large storage volumes.

In a RAID 1+0 configuration, all HP Smart Array controllers can

• Sustain multiple drive failures.

• Sustain an entire bus failure if the drives are equally distributed across buses.

• Service I/O requests to all operational drives in a degraded condition.

• Survive n/2 drive failures, where n is the number of drives in the array, as long as one member of each mirrored pair survives.

Note

RAID 1+0 can support multiple drive failures when multiple drives that fail are not in the same mirrored pair.

For RAID 5, HP recommends that no more than 14 (8 is optimal) physical drives be used per logical drive. Because logical drive failure is much less likely with RAID ADG, however, HP supports the use of up to 56 physical drives per drive array when running this fault-tolerance method.