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What is RAID?

Last modified: July 2, 2022
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What is RAID?

RAID, also known as a Redundant Array of Inexpensive Disks, is a reliable technique for effectively storing data. To make use of many hard drives integrated into bigger volumes, it employs strategies including striping, mirroring, and parity.

RAID, however, has two primary objectives. Your data can be configured to be mirrored. It provides you with a chance to maybe survive a disastrous disc crash (depending on the configurations). Making data reading and writing faster is one of its key goals. Some RAID setups combine the two.

RAID won’t save your data in the event of a catastrophic failure, even though you can recover data in some situations and setups. Take the case of all the drives failing. A solid backup schedule is therefore necessary to safeguard your data.

RAID 0, RAID 1, and RAID 5 are some of the more popular RAID configurations. RAID 01, RAID 10, and RAID 50 are just a few examples of configurations that incorporate two or more RAID levels. There are some RAID configurations that are available but very infrequently used, such as RAID 2, RAID 3, RAID 4, and RAID 03.

Another configuration style exists; it is known as JBOD. Just a Bunch of Disks is what it stands for. Any number of different drives can be combined into volumes using this arrangement. This is a non-standard RAID design that doesn’t offer data redundancy or recovery, in our opinion.

RAID can be implemented via hardware or software. If the RAID is software-based and its hardware is based on a RAID controller extension card using one of your expansion slots for motherboards, your operating system will control it. Through your own BIOS, you can set up a hardware RAID card.

RAID

Has many configurations based on your needs and the hardware’s availability. The majority of those configurations are built upon one of the first two layers, individually or in combination. You can grasp any of the others if you understand RAID level 0 and level 1. RAID 0 and RAID 1: what are they?

RAID 0

Data can be stored on a disc via striping. Across each disc in the array, the data is written in stripes. Although striping increases read/write speeds, it offers no drive failure prevention. You must employ other strategies, such as parity and/or mirroring, in order to have such protection.

The RAID controller generates parity, a redundancy method that functions something like a data checksum. It makes use of a parity bit, which computes the sum of the data in a stripe. This bit may be distributed across the discs in the volume or may be on a separate drive, as is typical for RAID level 5. The RAID can be reconstructed using the parity in the case that one of the drives fails.

RAID 1

Another method of data storage is mirroring, which is essential to RAID’s ability to recover from a drive failure. A duplicate of the data is present on another volume because the volume(s) are mirrored. In order to achieve redundancy and recoverability using this technology, you need twice as many hard drives as you would need for a server without RAID. While read rates are slower due to information being simultaneously written on both sides of the mirror, reading/writing information is unaffected if one of the mirrored volumes fails because the RAID can still reach the other side of the mirror.

RAID 0, RAID 1, RAID 5, and RAID 10 (sometimes known as 1+0) are the most used RAID levels. As listed below, each of them has unique benefits and drawbacks.

Level 0 - stripe

  • Minimum number of drives: 2
  • R/W Speed: Excellent
  • Data recovery: none, no mirror

Level 1 - mirror

  • Minimum number of drives: 2
  • R/W Speed: Good
  • Data recovery: The mirrored volume can be recovered in most instances.

Level 5 - striping with parity

  • Minimum number of drives: 3
  • R/W Speed: Excellent
  • Data recovery: no mirror, however, the RAID can be rebuilt from parity in some instances

Level 10 -striped and mirrored volumes with parity

  • Minimum number of drives: 4
  • R/W Speed: Excellent

RAID 1+0, often known as RAID 10, is a combination of RAID 1 and RAID 0 and can therefore boost read/write throughput while still ensuring data recovery. At least four identical drives are necessary for a RAID 10.

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