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Everything You Need to Know about RAID Levels

As businesses expand, the demand for stable and robust infrastructure arises. One of the essential characteristics of a scalable system is good memory management. So, in this article, we are going to look at RAID, which stands for Redundant Array of Inexpensive (or ‘Independent’) Disks.

A RAID-enabled system typically uses two or more hard disks to boost the performance of a server or network-attached storage (NAS) unit. In addition to this, RAID provides some amount of fault tolerance in the digital storage device. In other words, the RAID system creates a safety net that enables the hard drive to continue functioning even when some of its components are damaged. This provides an extra layer of data protection by ensuring that data is not lost in case some elements in your hard drive fail.

How you configure the fault tolerance depends on the RAID level that you have set. The different RAID levels represent various configurations that are designed to provide different combinations of performance and data protection.

What is RAID?

RAID is a form of virtualized storage technology that is used to configure multiple hard drives in varying arrangements to achieve certain goals such as enhanced performance and better capacity.

There are two types of RAID storage; hardware and software. Hardware RAID uses a processor and dedicated controller within the hard disk to control memory as desired, whereas software RAID manages the memory architecture via the operating system (OS). Let us now look at the various levels of RAID that a hard disk can be configured to.

RAID 0

RAID 0 (also commonly known as disk stripping) is a configuration whereby a stream of data is split into chunks and then stored on different hard disks. So, when the system needs to recall data, it can read the data from all the individual disks simultaneously and create the entire data as it was before being subdivided.

The RAID 0 system is very advantageous because the speed of read-write operations is significantly increased. This makes it particularly desirable in situations where performance is a priority over everything else. In the RAID 0 configuration, the total capacity of a hard disk is the sum of the capacities of individual disks. The one downside of this system is its lack of redundancy, which essentially means that there is no duplication of data. So, if one hard disk fails, the entire data can be rendered worthless since the hard disk won’t be able to recreate it.

Pros:

  • Boosts performance for read-write operations
  • Storage space is fully utilized

Cons:

  • There is no duplication of data

RAID 1 (also known as data mirroring)

RAID 1 is a fault-tolerance configuration where data is copied or duplicated in multiple disks. The system provides impressive fault tolerance because the other hard disks can continue to work seamlessly even if one of them malfunctions or fails. In addition to this, it improves read speed since the data in different hard disks can be recalled simultaneously. Unlike RAID 0, however, the write speed with RAID 1 can be a lot slower since all drives must be updated every time new data is written. Moreover, a lot of space is used up to duplicate the data, which consequently increases the cost of storage.

Pros:

  • Data is not lost in case of disk failure since there are duplicates
  • The speed of read operations is increased

Cons:

  • Duplicating data leads to wastage of space, which increases the cost of storage
  • Speed of write operations is reduced

RAID 4

This is a RAID configuration, which combines elements of both RAID 0 and RAID 1. Just like with RAID 0, data is stripped down and stored in multiple hard disks while parity information is also stored in its dedicated hard disk to achieve a level of redundancy. Organizing the storage in this way ensures that data can be recreated using the parity information in case one hard disk is fried.

In this system, space is utilized much better than RAID 1 since storing parity information uses up less space than mirroring the entire data. However, write speed is reduced since all the parity information is contained in a single hard disk, which must be updated every time new data is introduced.

Pros:

  • Performance of read operations is boosted
  • More efficient data redundancy

Cons:

  • Write speed is slowed down
  • Data redundancy can be lost in case the parity disk crashes

RAID 5

It is very similar to RAID 4, but instead of storing parity data in a single disk, it is distributed over all the disks. This is advantageous for two main reasons. First, it eliminates any bottlenecks when it comes to reading data since parity stress is evenly spread out across multiple disks. In addition to this, the risk of losing data redundancy is eliminated since parity information is not held in a single disk. So, even if one of the disk crashes, the data can be reconstructed from the remaining ones that are still functional.

Pros:

  • Better write speed
  • Data redundancy is not lost in case one disk fails

Cons:

  • Cannot handle more than one disk failure

RAID 6

This configuration uses double parity blocks instead of one, thus providing better data redundancy than RAID 5. In other words, the fault-tolerance is raised up to two drive failures. This makes RAID 6 VERY efficient when it comes to maintaining large data storage systems.

Pros:

  • Provides better data redundancy since it can handle up to two hard disk failure

Cons:

  • Has a higher parity overhead compared to RAID 5

RAID 10

It is a hybrid system that combines the performance aspects of RAID 0 and the data redundancy of RAID 1 to provide the best of both worlds. In this configuration, several RAID 1 blocks are stacked together to create a setup that is similar to RAID 0. This system is often used in scenarios where both huge disk performance and data redundancy are required.

Pros:

  • Increased fault tolerance
  • Better read-write performance

Cons:

  • Price per unit memory can be quite high due to data mirroring

In Conclusion

Having a good grasp on the different levels of RAID is vital when it comes to developing data storage systems that suit the needs of your organization. By finding the right RAID configuration, you can strike the delicate balance between performance and data protection to ensure that your storage infrastructure is up to the tasks that your business requires of it.

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