User Guide

5
WHAT IS RAID?
RAID (redundant array of independent disks) technology manages multiple disk drives to enhance
I/O performance and provide redundancy in order to withstand the failure of any individual
member without loss of data. The following RAID-related terms are used in this manual.
Disk Striping (RAID 0): Striping is a performance-oriented, non-redundant data mapping
technique. Striping arrays use multiple disks to form a larger virtual disk.
Disk Mirroring (RAID 1): Disk mirroring creates an identical twin for a selected disk by having
the data simultaneously written to two disks. If a read failure occurs on one drive, the system
reads the data from the other drive.
Mirrored-Striping (RAID 0+1, or RAID 10): A Mirrored-Striping Set provides the performance
enhancements of Striping and the data availability and integrity of Mirroring. When data is
written to a Mirrored-Striped Set, a second (Mirrored) virtual disk is created, as well.
Parity RAID (RAID 0): Parity, or RAID 5, adds fault tolerance to Disk Striping by including
parity information with the data. It uses less capacity for protection and is the preferred method
to reduce the cost per megabyte for larger installations.
Just a Bunch of Disks (JBOD): The JBOD is a virtual disk that can either be an entire disk drive
or a segment of a single disk drive. For this card, the JBOD function only supports one disk.