Disk arrays RAID: what is it, and what for?

Many users have heard about this concept, like disk arrays RAID, but in practice, very few people imagine what it is. But as it turns out, there is nothing complicated here. We will analyze the essence of this term, as they say, on the fingers, based on an explanation of the information for the average inhabitant.

What are RAID disk arrays?

First, let's look at the general interpretation that is offered by Internet publications. Disk arrays are entire information storage systems consisting of a bunch of two or more hard disks, serving either to increase the speed of access to stored information, or to duplicate it, for example, while saving backup copies.

In this bundle, the number of hard drives is theoretically limited in terms of installation. It all depends on how many connections the motherboard supports. Actually, why are disk arrays used RAID? Here we should pay attention to the fact that in the direction of technology development (relatively to hard disks) they have frozen at a single point for a long time (spindle rotation speed 7200 rpm, cache size, etc.). The only exception in this plan is only the SSD models, but they mainly produce only an increase in volume. At the same time, in the production of processors or slats of RAM, progress is more tangible. Thus, due to the use of RAID-arrays, there is an increase in performance gain when accessing hard drives.

RAID disk arrays: types, purpose

As for the arrays themselves, they can be conditionally divided according to the numbering used (0, 1, 2, etc.). Each such number corresponds to the performance of one of the declared functions.

The main ones in this classification are disk arrays with numbers 0 and 1 (it will be further understood why), because they are assigned the main tasks.

When creating arrays with multiple hard drives connected, you must first use the BIOS settings, where the RAID configuration section is set to RAID. It is important to note that connected disks must have absolutely identical parameters in terms of volume, interface, connection, cache, etc.

RAID 0 (Striping)

Zero disk arrays are essentially designed to speed up access to stored information (write or read). They, as a rule, can have a bundle of two to four hard drives.

But the most important problem here is that when you delete information on one of the disks it disappears on others. The information is written as blocks sequentially on each disk, and the performance increase is directly proportional to the number of hard drives (that is, four disks are twice as fast as two). But the loss of information is only due to the fact that the blocks can be on different disks, although the user in the same "Explorer" sees the files in the normal display.

RAID 1

Disk arrays with a single designation refer to the category Mirroring (mirroring) and serve to save data by duplicating.

Roughly speaking, in this situation, the user loses a bit in performance, but can be sure that if the data from one section disappears, they will be saved in the other.

RAID 2 and higher

Arrays with numbers 2 and higher have a dual purpose. On the one hand, they are intended for recording information, on the other hand they are used for error correction.

In other words, disk arrays of this type combine the capabilities of RAID 0 and RAID 1, but among computer scientists, they are not very popular, although the basis for their work is the use of the Hamming code.

What is better to use in practice?

Undoubtedly, if you intend to use resource-intensive programs on your computer, for example, modern games, it's better to use RAID 0 arrays. In case of working with important information that you need to save in any way, you'll have to turn to RAID 1 arrays. Due to the fact that the bundles with numbers from Two or more popular and never became, their use is determined solely by the desire of the user. By the way, the use of zero arrays is practical even if the user often downloads multimedia files on the computer, for example, movies or music with a high bitrate for MP3 or FLAC.

In the rest, you will have to rely on your own preferences and needs. It is from this that the application of this or that array will depend. And, of course, when installing a bundle, it's better to give preference to SSD disks, since they already initially have higher read and write rates compared to conventional hard disks. But they should be absolutely identical in their characteristics and parameters, otherwise the connected combination will simply not work. And this is one of the most important conditions. So you have to pay attention to this aspect.