Why RAID? Let's Find Out about RAID server data recovery

Redundant Array of Independent Disks (RAID) is a disk subsystem that is used r
to increase performance or provide fault tolerance or both. RAID uses two or r
more ordinary hard disks and a RAID disk controller.

Advantages:

¢ The main advantage of a RAID drive is that it increases the performance and r
reliability of the system. The RAID drive is a convincing example that could r
be used in a server.

¢ Mirroring is the complete duplication of data. In other words mirroring is r
the 100% duplication of data on two drives. These are RAID 1 drives. No r
rebuild of data is necessary in case of disk failure due to 100% redundancy. r
Only copying to the replacement is necessary.

¢ Mirroring & Striping - The performance of a server increases when Disk r
stripping is done - RAID Level 0+1 requires a minimum of 4 drives to r
implement. This is actually done by the interleaving of bytes or a group of r
bytes. The interleaving of this sort is done across multiple drives. Reading r
and writing of the data are done in a simultaneous process. High I/O rates r
are achieved by striping RAID 1 segments.

¢ The RAID regularly checks for any possibility of a system crash by r
increasing the parity check.

¢ The concept of parity comes after the concept and application of mirroring. r
Data from the crashed system is matched with the data stored in the other r
disk. This is called Parity. Parity is used to calculate the data in the two r
drives and store the results in the third drive. In case there are more than r
two drives parity check is done on all of them and the results are stored on r
a completely different drive. The preferable device may be the RAID 3 (r
Striping With Dedicated Parity) or RAID 5 (Striping With Distributed Parity). r
Very high rate of transfer when data is being accessed in large chunks r
sequentially.

Disadvantages:

¢ A major disadvantage regarding the RAID drive is that drivers for a Network r
Operating System (NOS) need to be written. The most important usage of the r
RAID system is that it is primarily designed and widely used in a server. So r
when the server comes into the picture, there obviously has to be a network. r
Hence the device drivers should be included so as to design the system. The r
design is a quite complex process as far as the RAID is concerned.

¢ Administrators find it very difficult to configure a RAID system. The r
ability to dynamically enlarge the RAID server is also a complex process; r
especially for those administrators who are the IS managers and also LAN r
administrators.

¢ Another main disadvantage is that the system should support RAID drives. r
Most of the RAID drives include the different types like the RAID 0, RAID 1, r
and RAID 2 etc. Hence if the server system is using a different type of RAID r
drive and that is not supported by the system, then the problem of r
availability may arise.

¢ Initially one has to determine the type of RAID drives that is compatible. r
Different system supports different types of RAID drives. DGR (Storage r
Dimensions Dynamic Growth) technology allows the administrator of any network r
system to reconfigure the Storage Dimensions RAID System.

Though there are disadvantages, the RAID system offers a lot of expansion and r
constancy and the advantages are one up on disadvantages. Hence RAID is still r
the most widely used server.

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