Tech Guide: RAID 0, 1, 3 & 5

RAID is Redundant Array of Independent Disks. The purpose is to enhance performance and increase data redundancy.  It is also termed as Redundant Array of Inexpensive Disks. It is generally addressed as RAID array, although, an array is already included in the name.

It is a virtual data storage technology that uses multiple physical data storage units to form single virtual storage. RAID is combining a number of physical storages to create a logical storage.

Why do we need RAID?

The RAID technology has seen many transformations, improvements, and enhancements over past years. There are some very interesting conceptual improvements in the field of RAID from the time it was introduced. There are several levels of RAID by which the drives are locked together. They are termed with respective levels, these levels are denoted by numbers.

RAID was introduced as an aid to the information world, striving for more and more space. When the disks where less spacious and very costly, RAID technology came as an incredible measure to fulfill the needs of fast operation and fault tolerance.

So does it mean that RAID, commonly known as RAID array is equal to data backup? The answer would be a straight denial. RAID does not signify any kind of data backup, it's way different than that.

RAID does not give you protection against data loss due to a virus, malware, data theft, data corruption or any natural fault. So it does not have anything to do with backing up data. But it certainly provides safety against hardware failure. RAID is simply a measure of failure protection. In such cases, the hardware may fail, but the array remains intact and thus protecting your information.

There are certain levels of RAID denoted with respective numbers, let’s have a look at these RAID levels;



Raid 0 is devised to distribute the data across the drives. This allows higher read and write speed. 0 denotes the higher speed of read and write operation. The separate blocks move the data across multiple drives to enhance operating speed. This is termed as striped.

Though, there is one very important factor which should be kept in mind. RAID 0 does not offer any protection against drive failure. So at a time of drive failure, it leaves the computer with a lot of lost data. In a case when you are using an external drive or an alternate drive for RAID 0, you can lose a significant data. So when an external hard drive turns unreadable use software to recover data that has been lost.

Here are some of the features of RAID 0 listed;

  • It requires a minimum of 2 disks.
  • Has no data redundancy as there is no parity or mirroring involved.
  • Avoid using this for critical or sensitive systems.
  • It provides an excellent performance due to the striped blocks.


Raid 1 involves pairs of drives to read and write data during operation. This method is also called as mirroring. The drives involved, are parallel during every operation and participate equally. In the case of drive failure, the parallel drive can be used at the time of replacement of the damaged drive.

It is the easiest and simplest to implement RAID and create a security measure for drive failure. RAID is also one of the most convenient ways for failure protection and it takes a half of the total space on implementation. You can have as many pairs of RAID drives as you want. They will be helpful for securing your data.


Some of the features of RAID 1 can be enlisted as;

  • It requires a minimum of 2 disks
  • It delivers a good performance.
  • There is no parity involved and no striping done.
  • Great level of redundancy as the drives is mirrored.


Technical guide to RAID

This is one of the advancements in RAID technique which results in the high performance of disk drives. RAID 3 doesn’t use data blocks, instead, it uses a separate drive to store the parity information. RAID 3 has dedicated drives for data and uses striping across the blocks and a dedicated drive for storing parity. This increases the reliability.

Some of the features of RAID 3 are;

  • Uses multiple disks for data and a separate disk to store parity.
  • A good performance due to sequential read and writes technique.
  • It uses a byte by byte striping, this helps in increasing the performance.


This mode offers both data redundancy and performance. RAID 5 involves the use of three disks for execution and uses a one-third space for parity information. In RAID 5, it reads data and  writes across multiple disks using parity data distribution in all the drives using an array.

RAID array- RAID 5

“A parity data is a small amount of mathematically derived data that represents the larger amount of data, it has the ability to restore the large data.

Some of the important aspects of RAID 5 can be enlisted as;

  • It requires a minimum of three disks for the RAID 5 mode of operation.
  • It delivers a good performance due to striping.
  • Due to distributed parity, the data redundancy is outstanding.
  • Reduced cost for provision of high performance and data redundancy

There are some other techniques available and are under practice like RAID 4, RAID 1+0, RAID 2, RAID 6. Thus the evolution of RAID technology is one of the best moves towards enhancing performance. It is one of the best ways to ensure data redundancy.

Tech Guide: RAID 0, 1, 3 & 5 was last modified: December 7th, 2016 by John Harris

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