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Boost Up Your Hard Drive Performance with RAID Technologies

by: Kenneth Tello | 18 Dec, 2010 11:21:07

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RAID (Redundant Array of Independent Disk) is a hard disk technology developed to optimize hard drive performance by increasing reliability and storing functions through redundancy. Disk redundancy is achieved by joining multiple disks, forming a logical unit of independent disks. Designs of RAID array system involve two main goals: first is to increase reliability of data, and second is to boost up read/write performance of your hard drive. Though RAID distributes data on all disks in the array, the operating system control them as a single disk.

There are seven standard levels of RAID technologies which can be implemented to increase hard drive performance. Each RAID technology


RAID 0 is the first standard level of RAID technology. RAID0 implements a technique of writing fixed sized blocks multiple disks (without parity checking). Disks are divided into blocks of fixed size where data are written. Whilst RAID0 provides additional storage, it does not provide fault and redundancy tolerance. In addition data access (read/write) on RAID 0 is not centralized on a single unit, resulting to reduced input/output time. RAID 0 does not have error checking, so any error on data cannot be corrected. The main feature of RAID 0 technology is only to disperse hard drive I/O (does not improve data reliability). Hence RAID 0 is a tradeoff between increased storage and reduced I/O time vs. data reliability.


RAID1 technology implement a technique called “disk mirroring” in which the same data is recorded on 2 or more hard disks (mirrored sets). Unlike RAID0, RAID1 provides fault tolerance from error and failure checking through mirroring. RAID1 continues to function as long as there is at least on hard drive in the mirrored set that is functioning. In addition, data safety is also improved since you already have data backup in case fault occurs. RAID 1 increases the read performance of the hard drive, but there is a minimal time increase in write performance since 2 or more disks needs to be written with the same data.


RAID2 technology implements error checking technique called dedicated hamming code parity checking. RAID 2 strip data at a bit level and the disk is being synchronized by the controller, thus allowing high data transfer rates. Sadly, RAID2 is not currently in use.


RAID3 implements error checking technique through a dedicated parity disk. RAID3 is seldom used because of some reasons: it does not allow multiple requests simultaneously and it does not provide data correction once error/s has been detected. Nonetheless RAID3 offers high data transfer rates and is best for applications that demand long sequential read/write operations such as uncompressed video editing.


Unlike RAID2 and 3 which implements bit level striping, RAID4 implements block-level striping with dedicated parity. Using this design, data can be distributed throughout multiple disks. In addition RAID4 offers parallel access to independent disks, thus allowing I/O requests to be done in parallel. However, this does not guarantee increase in data transfer rate. RAID4 implements error checking mechanism using a dedicated parity stored on a separate parity disk. RAID4 can detect errors but it cannot correct the errors found.


RAID5 implements block-level stripping with distributed parity as error checking mechanism. Parity bits are distributed together with the data allowing only at least one drive to operate to continue its functions. Drive replacement is necessary on drive failure, but the array of multiple disks is not destroyed nonetheless. RAID5 offers error recovery when an error occurs on a single disk.


RAID6 is an enhanced version of RAID5; this time allows error recovery even when 2 disks failed. RAID6 technology also implements block-level stripping with parity is distributed together with the data.

Benefits of Using RAID Technologies

Here are some of the most common benefits of using RAID technologies on your hard drive (depending on the type of RAID used).

  • Increase performance and reliability of the hard drive’s read/write operations.
  • Frequent checking of possibilities of system crash through parity checking.
  • Very high data transfer rates for block-level stripping (RAID0, 1, 5, and RAID6).
  • Disk mirroring is the classic example of disk redundancy.

You can choose any of these seven RAID technologies to increase performance and reliability of your hard drive. But always remember to choose the one that suits your needs.

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