User guide

Hard Drive Arrays
■ Data protection
■ Performance enhancement
■ Capacity changes
■ Data reliability
The RA4000 Controller provides several options to produce data redundancy
for a more reliable system including distributing data, fault-tolerance methods,
assigning online spares, and rebuilding data.
During configuration, you will need to make RAID (Redundant Arrays of
Inexpensive Disks) level choices. RAID is a term used for an array technology
that provides data redundancy to increase system reliability and performance.
There are several RAID levels ranging from RAID 5 to RAID 0. The RA4000
Controller provides the following levels of RAID:
■ RAID 5 - distributed data guarding
■ RAID 4 - data guarding
■ RAID 1 - drive mirroring
■ RAID 0 - no fault tolerance (data striping only)
The fault-tolerance method you choose affects the amount of available disk
storage capacity and performance of your drive array. The following chart lists
the supported RAID levels and illustrates how the fault-tolerance method you
select affects the performance and capacity.