User`s guide

StorageWorks RAID Array 200 Subsystem Family
RAID Overview
RAID (redundant array of independent disks) is a modular, integrated, end-user
solution that provides three main benefits:
•
Improved data availability
•
Improved I/O performance
•
Increased scaleability
A RAID array is a set of multiple disk drives and a specialized array controller that
manages how data is distributed across disk drives.
Data for a given file is divided into segments, which can be written across multiple
drives. A segment is a group of blocks that is continuous data which can be stored on
a disk drive. By using more than one drive, the array can provide higher data transfer
rates when compared to a single large drive. Depending on the RAID level used,
arrays can also provide redundancy to protect data availability.
As you configure your subsystem, select the RAID level appropriate for your
computing environment.
Raid Levels
RAID 0, 1, 0 + 1, 5 and JBOD are supported by the StorageWorks RAID Array 200
Subsystem Family and offer data redundancy/performance.
Raid 0
RAID 0 stripes data across the drives in the array, one segment at a time. RAID 0
offers a high I/O rate, but is a nonredundant configuration. No array parity
information is generated for reconstructing data if a drive fails.
Raid 1
RAID 1 transparently mirrors data by writing data to two drives simultaneously. This
is the simplest way of to achieve data redundancy. The cost of data storage is greater
than for a single drive, since double the disk space is required. However, RAID 1 is a
consideration for users where reliability is most important.
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