Raid Types

Overview

A Redundant Array of Inexpensive Disks (RAID) is a system that allows computers to increase options for storage reliability by arranging devices into redundant arrays.

RAID is a computer data storage scheme that allows you to divide and replicate data between several hard disk drives. RAID architecture is designed to increase data reliability and to improve input and output performance. Multiple disks that use RAID technology are known as a RAID array. Even though a RAID includes a group of disks, you should think of it as a single disk.

Depending on the design and function, RAID is classified into different types, which are designated by numbers. RAID 1 includes mirrored drives, RAID 2 servers a purpose of hamming codes for error correction, and RAID 3 has a single check disk per group. RAID 4 independently reads and writes, and RAID 5 spreads data across the disks.

RAID systems can be hardware or software based. Software works through the kernel disk code, and hardware connects to an SCSI controller. Because of today's fast CPUs, software RAID can actually outperform hardware RAID.

Benefits

The benefits of RAID depend on your business's needs. Mostly, RAID systems are used to improve data reliability, availability, and serviceability. You can increase your capacity to store information, which is especially important if your business relies on computers. A combination of smaller and inexpensive disk drives will perform better than one large and expensive disk drive.

How It Works

The redundancy created by RAID allows extra data to be written throughout the array. As a result, one failed disk will not cause data loss. The failed disk can be replaced with a new one. Any extra data can be loaded on the new disk.

With a 2 disk RAID 1 configuration, if both the disks operate independently, each disk would store its own data in addition to the data of the other disk.

The array is presented to the computer as a single unit through hardware or software configurations. When RAID is hardware based, the computer assumes that one disk drive is attached. When RAID is software based, the hardware recognizes multiple drives while the software recognizes only one single drive.

High computing power is required to read and write data in a RAID array. This method also requires a separate controller for operation. As a result, off-board RAID processors have gained popularity.

If you choose to work with RAIDs, make sure that you develop backup plans to minimize potential for data loss.

Companies/Brands

HP, Adaptac, and IBM develop RAID hardware. Midwest Data Recovery Inc., Microcom RAID Data Recovery, Optimum Data Recovery, Chicago Data Recovery, and Disk Internals offer RAID recovery services.