Promise Technology FastTrak TX4000 - Manual (Page 52)

FastTrak TX4000 User Manual
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Disk Array Terms
Disk Array Description
A disk array is formed from a group of two 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 redundancy 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 setup Auto Setup (1) option will configure
your system.
There are three disk array types in two categories that can be installed on the
FastTrak TX4000 card. Striping is in the Performance category while Mirroring,
Striping/Mirroring are in the Fault Tolerance 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
Fault
Tolerance
Capacity
No. of
Drives
RAID 0
(Striping)
Highest No
No. Drives x
Smallest Size
2 to 4
RAID 1
(Mirroring)
Normal Yes Smallest Size Drive 2
RAID 0+1
(Stripe/Mirror)
High Yes
2X Smallest Size
Drive
4