User`s manual

16
Understanding Disk Array Concepts
About MBFastTrak133 Lite Disk Array Adapter
MBFastTrak133 Lite is a high performance Ultra ATA RAID controller that features parallel data channel
operation and an onboard BIOS. The two channels on the MBFastTrak133 Lite support parallel operation
that allows for overlapped I/O under multi-tasking operating systems and sharing the workload between
multiple drives.
About Adapter BIOS
The MBFastTrak133 Lite contains a BIOS code that extends the standard disk service routine provided
through Int13. The BIOS is bootable for DOS and other operating systems that rely on the system BIOS for
drive operation. MBFastTrak133 Lite can support drives and disk arrays with capacities exceeding 8.4 GB
using Extended Interrupt13 support. When the MBFastTrak133 Lite BIOS appears during bootup, users can
press <F2> to enter the FastBuild
TM
setup to select from menu settings.
FastBuild
™
Auto Menu Setup
This setup utility is used to build and manage MBFastTrak133 Lite disk arrays. The utility is menu driven and
features the <1> Auto Setup option that uses a simple, interactive setup process. Once the array is built, all
the array members store the configuration information in the drive’s reserved area. See Chapter 4 that
provides descriptions of individual functions.
Reserved Sector
Array configuration data about the drive member and other members in the disk array are saved on a special
location on the disk drives called the reserved sector. If any member of the array becomes corrupt or lost,
the redundant configuration data on the other members can be used for rebuilds.
Disk array members do not have a “memory” of their drive positions. This allows drives to be placed on
different MBFastTrak133 Lite connectors within the system without reconfiguring or rebuilding.
Disk Array Terms
Disk Array Description
A “disk array” is formed from a group of 2 or more disk drives which 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 in parallel 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 is coded in
their “reserved sector” with 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 MBFastTrak133 Lite. 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 with the
R
edundant
A
rray of
I
ndependent
D
isks technology, or RAID. The RAID levels supported are 0 and 1.