The major RAID Concepts are Physical and Logical Arrays and Drives, Mirroring, Duplexing, Striping and Parity. First, we look at physical and logical arrays and drives: The structure of RAID is like an array. As we know, an array is a collection of drives that is configured in a particular way. The number of drives and the data is split between them to determine the RAID level, the capacity of the array, performance and data protection characteristics helps in deciding what types of arrays needed to be set up, and how to configure them. Second, we look at Mirroring:

The advantage of mirroring is to provide redundancy of data and also quick recovery from a disk failure. All the data which is on the second drive, is ready to be use if the first one fails. The disadvantage of RAID 1 is expense. Results are as not as good as other RAID levels. Third, we look at the Duplexing: Duplexing yields superior results then mirroring because of availability, it provides the protection against drive failure that mirroring does. It is expensive more than mirroring. Fourth, we look at striping: Striping is done at byte level. Byte level striping means file is divided into "byte-sized pieces".

The first byte is sent to the first drive, then the second byte is send to the second drive, and so on. Byte level striping is done at 512 bytes. Block level striping means that the file is split into blocks of a certain size and is distributed to the various drives. The size of the blocks is called the stripe size. Finally, parity: The term parity is used in connection of system memory error detection. The parity which is used in RAID is nearly similar to parity RAM.

The parity is simple: take N pieces of data, and from them, calculate the extra amount of data. Take the N+1 amount of data and store it in N+1 drives. If you lose any one of the N+1 pieces of data regardless of which piece is lost. Parity protection is used with striping, and the N pieces of data are of the blocks distributed across the drives in the array.

The major RAID Issues are RAID Performance Issue & RAID Reliability Issue. The RAID Performance Issue: RAID was developed for protection of data in order to find the fault tolerance. The performance could be increases RAID is parallelism. The ability to access multiple disks and allows for data to be written to or read from a RAID array faster than a single drive. RAID Reliability Issue: The RAID affects important reliability factors such as, For example, a commonly-heard phrase is that RAID improves hard disk reliability, but that is not an true.

The truth depends to on how you define reliability and what do you mean reliability of the individual drives, or the whole system are about the data, or the hardware itself. The performance could be improved through the use of RAID for businesses where the protection of critical data is important factor.

Data Recovery Software - RAID Recovery

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RAID 3
RAID 4
RAID 6
RAID Implementation
RAID Parity
Resizing RAID regions
Testing RAID Drives
General Concept - RAID
Single RAID level
RAID Parity Corruption
Multiple / Nested RAID level
Bunch of Hard Disks
Data Loss from RAID Servers
Serial ATA RAID
RAID Data Recovery
Comparision of RAID Levels
RAID Toolbox
SCSI RAID
RAID Performance
Storage Controllers - RAID
MAC- RAID Installation
RAID Technology
RAID Cost
Windows Server Installation

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