Hp StorageWorks 1500cs Modular Smart Array Manual do Utilizador descarregar pdf (Página 67)

Drive arrays and fault-tolerance methods 67

Item RAID 0 RAID 1+0 RAID 5 RAID 6 (ADG)

Tolerates simultaneous failure of

more than one physical drive

Only if no two

failed drives are

in the same

mirrored pair

No Yes

Read performance High High High High

Write performance High Medium Low Low

Relative cost Low High Medium Medium

*Values for the fraction of drive space usable are calculated with these assumptions: (1) all physical drives in the

array have the same capacity; (2) online spares are not used; (3) no more than 14 physical drives are used per array

for RAID 5; and (4) no more than 56 drives are used with RAID 6 (ADG).

Selecting a RAID method

NOTE: Not all controllers support RAID 6 (ADG).

Most important criterion Also important Suggested RAID level

Fault tolerance Cost effectiveness

I/O performance

RAID 6 (ADG)

RAID 1+0

Cost effectiveness Fault tolerance

I/O performance

RAID 6 (ADG)

RAID 5 (RAID 0 if fault tolerance is not required)

I/O performance Cost effectiveness

Fault tolerance

RAID 5 (RAID 0 if fault tolerance is not required)

RAID 1+0

Alternative fault-tolerance methods

Your operating system may also support software-based RAID or controller duplexing.

• Software-based RAID resembles hardware-based RAID, except that the operating system works

with logical drives as if they were physical drives. To protect against data loss caused by physical

drive failure, each logical drive must be in a different array from the others.

• Controller duplexing uses two identical controllers with independent, identical sets of drives

containing identical data. In the unlikely event of a controller failure, the remaining controller and

drives will service all requests.

Neither of these alternative fault-tolerance methods supports online spares or automatic data recovery, nor

do they support auto-reliability monitoring or interim data recovery.

If you decide to use one of these alternative methods, configure your arrays with RAID 0 for maximum

storage capacity and refer to your operating system documentation for further implementation details.

1 2 ... 62 63 64 65 66 67 68 69 70 71

Sem comentários

Hp StorageWorks 1500cs Modular Smart Array Manual do Utilizador Página 67