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What is it, what is it for and how does a RAID work and what types and levels are there?

What is it

RAID technology has been used for several years, it is especially used to carry out critical data operations, where you cannot lose a single bit. This technology is used especially by professionals or companies that require a lot of care and attention, where losing information can cause big problems. Its main function is to protect user information, thus providing security and trust.

Usually, we have been used to seeing computers with one or two hard drives, but this technology is responsible for combining several disks (HD) in order to form a single drive , and all the data that is handled will be stored in each one of them, despite being several all work as one. The goal of all this is, if one of the disc starts to fail or is damaged, the others continue to work correctly, therefore, your information will continue to work as if nothing happens with the team.

Due to the importance of being able to manage and know what a RAID is, “Redundant Array of Independent Disks” here we will show you a bit of what are its levels and its main types s so you can keep it in mind when you want to implement it in your business.

What is RAID technology really and what applications does it have?

¿Qué es realmente la tecnología RAID y que aplicaciones tiene?

As we mentioned earlier this type of technology is responsible for allowing the connection of 3 or more hard drives simultaneously on the same computer, in order to always provide you with a user support in case there is any kind of inconvenience with one of them.

RAID is responsible for unifying all these hard drives, so that it will appear as a single HD. This allows the user to have greater security in their data, especially for those that are really important and cannot be lost, it also allows greater speed for access.

The “Redundant Array of Independent Disks” is characterized by providing different advantages to each of its users, among them we find the following:

  • Take all the capabilities of hard drives that are connected to form a single volume layer.
  • Increase access speed. To do this, separate all data into several blocks to make reading and writing much faster.
  • When using this technology, the speed of the storage will increase as hard drives deteriorate.
  • Offers a high level of tolerance

How many RAID levels are there and what are their characteristics?

It is important to mention that RAID is capable of supporting different configurations , they include levels 0, 1, 2, 3, 4, 5 and 0 + 1 , in total there are 6 levels that exist, each of them fulfills an important function in its operation. Because of this we will explain each of these levels and their main characteristics.

Level 0

Nivel 0

It is also known as Striping and is considered as a data emptying technique . This means that the data will be written to the disk drive, the same will be broken into blocks and distributed to the disks that are part of the set , which will allow higher performance as well as safer storage.

When using level 0 , at least one nth of each of the data will be found on each of the disks. One of its main advantages is that it will provide high performance in terms of writing and reading. But, this level 0 can only be used for those applications that are compatible or support loss of access to data, which will be possible to obtain from different sources.

Level 1

Nivel 1

Level 1 or Replicas, is one of the techniques most used by RAID technology, and this has the main function of providing identical data when writing in each of the hard drives that make up part of the set leaving a copy in each of them.

This technique is characterized by allowing a high level of data transfer when they are read but usually they act independently . In addition, it offers better reading performance . As for its storage capacity, it is exactly the same as the hard drive replicas on the hardware .

This level 1 is responsible for making each one of the disks identical to each other and among its main applications is intensive read OLTP and other data Transferable to provide high performance. Applications such as email, operating systems, intensive random access environments, readings and application files often benefit from this level 1.

Level 2

Nivel 2

This is responsible for detecting failure mechanisms in the disks of the set to work in memory . That is, level 2 will be in charge of constantly checking each of these hard drives. But it should be noted that this level is currently one of the least used , since almost all discs or the vast majority leave the factory, that is to say new and usually already bring this type of Failure detection included , so RAID 2 often does not end up being necessary.

Level 3

Nivel 3

At this level all the data that is stored on the hard drives is divided among all that make up the set, but except for one, in which it is responsible for storing parity information . All data bytes have their parity, this is what allows errors to be identified and stored on a specific disk.

This level 3 is characterized by offering a high percentage of transfer as well as a high reliability in the information provided. In addition, it is responsible for providing a very good performance for images, videos , natural sciences or any other sequential application. And in order to function, it requires at least the use of 3 HD.

However, it still does not fit very well for those applications that require simultaneous inbound and outbound operations of multiple users.

Level 4

Nivel 4

It is responsible for using the parity that is concentrated in a single unit in order to protect each of the data. Level 4 is considered the best for what is the transfer of inputs and outputs and not for the transfer of large files.

This level is rarely used with technologies such as write cache and with it you cannot install Red Hat Enterprise Linux.

You can also say that it is very similar to RAID 3 but this presents is a block parity and is said to be the capacity of the member disks minus the capacity of a member disk.

Within this level each of the recording operations that are carried out will have the need for a new parity calculation, this will allow you to have a little more confidence in the storage of the information obtained.

Level 5

Nivel 5

It is the most common of all and is responsible for distributing parity among each of the member units. Level 5 has the function to eliminate the bottleneck of the level writing 4 , that is, the process used to calculate parity. This level is usually used to the backward write cache in order to reduce asymmetry.

Regarding the storage capacity of this level will be equal to that of all member units, the capacity of RAID 5 will be equal to the capacity of all partitions of each One of the members. In addition, it is responsible for reducing the required components when it is providing good availability and good performance for each of the readings.

Level 0 + 1


This is one of the most striking, since it is a combination between what is level 1 and level 0, where the data will be divided between them to improve entry.

Another feature is that can duplicate all your information using other discs in order to provide better support for all information. In such a way, you can ensure a good entry with the level 0 accompanied by the redundancy of 1.

Unlike the other levels, it is necessary that at least 4 disks be necessary to mount what would be RAID 0 + 1 . Its main advantage is that it is the fastest and safest of all, which could be worth using the 4 units necessary to carry out its operation.

What types of RAID exist?

As for the types of RAID we will find 2 completely different, one of them is based on hardware while the other is based on software . Like everything, each of them has its pros and cons

hardware-based RAID

It is currently the most up-to-date and this is because it does not have the need to depend on an operating system. In addition, it is quite fast allowing you to explore each of its resources but, no everything can be wonderful and since everything good has something bad, this time is no exception and that in terms of its cost it is quite high which becomes its main disadvantage.

Another aspect is that you usually use devices or also known as RAID controllers, these can be added to the motherboards of computers.

Software based RAID

Unlike the previous one, this one is not very used at present, since in terms of its operation it has several disadvantages with respect to hardware, it is usually much slower in its operation, its configuration is much more complex and depends on an operating system so you can have a satisfactory experience.

However, it should be noted that is usually much cheaper than the previous one , but if what you are looking for is quality and good results, the cost is set aside. Finally, this software is dependent on the processing power of the computer being used.