User manual

FastTrak TX2000™ Series User Manual
44
Disk Array Terms
Disk Array Description
A “disk array” is formed from a group of 2 or more disk drives that appear to the system as a
single drive. The advantage of an array is to provide better throughput performance and/or data
fault tolerance. Better performance is accomplished by sharing the workload among multiple
physical drives. Fault tolerance is achieved through data redundant operation where if one (or
more) drive fails or has a sector failure, a mirrored copy of the data can be found on another
drive(s).
For optimal results, select identical
Ultra ATA/133 drives to install in disk arrays. The drives’
matched performance allows the array to function better as a single drive.
Disk Array Member
The individual disk drives in an array are called “members.” Each member of a specific disk
array has coded in its “reserved sector” configuration information that identifies the drive as a
member. All disk members in a formed disk array are recognized as a single physical drive to
the system.
Disk Array Types
For most installations, the FastBuild
TM
setup “<1> Auto Setup” option will configure your
system.
There are four disk array types in three categories that can be installed on the FastTrak TX2000
card. Striping is in the Performance category while Mirroring, Striping/Mirroring are in the Fault
Tolerance category. Spanning (JBOD) is in the Capacity category.
Disk arrays within the Performance and Fault Tolerance categories conform to the Redundant
Array of Independent Disks technology, or RAID. The RAID levels supported are 0, 1, and 0+1.
RAID Level Performance Capacity
# of
Drives
RAID 0 (Striping)
RAID 1 (Mirroring)
RAID 0+1 (Stripe/Mirror)
JBOD (Spanning)
Highest
Normal
High
Normal
# Drives x Smallest Size
Smallest Size Drive
2 x Smallest Size Drive
100% of All Drives
2 to 4
2
4
2 to 4