User guide

1-4 Compaq Smart Array 431 Controller User Guide
Drive Arrays
RAID technology distributes data across a series of hard drives to unite
physical drives into one or more logical drives. Distributing the data makes it
possible to access data concurrently from multiple drives in the array, yielding
I/O rates faster than non-arrayed drives. Each logical drive in the array may be
set to a different fault-tolerant configuration. The Smart Array 431 Controller
manages the drive array independent of the host processor.
The Array Configuration Utilities are used to help you configure the hardware
in the way that best suits your needs.
CAUTION: It is recommended that any time you move drive arrays or change
your configuration you should back up data.
See Appendix D, “Understanding Drive Arrays,” for more information on
drive arrays. For information on configuring your drive arrays using Option
Rom Configuration for Arrays and Compaq Array Configuration Utility, see
Chapter 6, “Array Configuration Utilities.”
Fault Tolerance
Fault tolerance refers to various methods used to protect data from being lost
in the event of a hardware failure somewhere in the storage system. Each
method has its advantages, so choosing one requires careful planning for your
particular requirements.
The fault tolerance methods supported by the Smart Array 431 Controller and
the Compaq Array Configuration Utility include:
■ Distributed data guarding (RAID 5)
■ Drive mirroring (RAID 1) or (0+1)
■ No fault tolerance (RAID 0)
■ Further data protection can be achieved by assigning an online spare to
any RAID 1 or RAID 5 configuration
See Appendix D, “Understanding Drive Arrays,” for more information on
these fault tolerance methods. See Chapter 6, “Array Configuration Utilities,”
for information on configuring your system using one of the fault-tolerance
methods.