Do not be intimidated by an unfamiliar word – we will tell you what kind of RAID it is and how it can be useful even for an ordinary user.
Every year, the performance of computer hardware is increasing at a high rate. Processors are equipped with more and more cores and threads, and video cards conquer higher chip frequencies. However, as far as hard drives are concerned, while their speed limit is frozen at 7200 rpm.
HDD specifications have recently changed only in terms of volume, but not speed. SSD-drives can correct this situation, but, as a rule, they are much more expensive and have a relatively low resource potential. Even before the advent of SSDs in 1987, the so-called RAID arrays were invented. Below we will tell you what it is, what types of arrays are, and how they can be useful to an ordinary user.
What is a RAID array?
RAID (Redundant Array of Independent Disks) is a data virtualization technology that combines multiple disks into a logical element to improve performance. Accordingly, the minimum number of disks required is 2, but more may be required. It all depends on what kind of array you need and for what.
RAID 0
The principle of operation is striping
An array in which information is divided into blocks of equal length, and then written one by one to each disk in the structure. The main purpose of such a system is the actual increase in performance by 2 times, while you will have access to the full volume of all disks.
An unlimited number of discs can be used. If the disks have different speed indicators, then the final result will be calculated for the slowest HDD. Allows you to combine disks of any size. For example, 320GB + 1TB + 3TB will function as expected.
Here are some examples to better explain these principles.
Suppose you have two disks with a write speed of 200 MB / s and a capacity of 1000 GB. By creating RAID 0, you get 400 MB / s write speed and 2000 GB free space. That is, you seem to increase productivity by distributing tasks among all participants in the system.
If one of the disks is 500 GB, and the other is 1000 GB, then the same 1500 GB will remain for your needs.
The most rational option for using this technology is if you have hard drives with the same technical characteristics. The connection interface matters. Let’s say two drives connected to SATA 1 and SATA 3 will both run at the speed of the slowest link.
However, such a scheme is not without its drawbacks. In addition to the difficulties with technical characteristics, you can easily lose all your data if at least one hard drive fails. Due to the fact that information is split and written in parallel on two disks, one file can be stored simultaneously on two or more media. If such a system is built of 4 “screws”, then the breakdown of even one is the inevitable collapse of all stored information. So don’t forget about backups if you’re using RAID 0.
Advantages
High performance
Disadvantages
Low reliability
Difficulty matching discs with the same characteristics
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RAID 1
The principle of operation is mirroring. The simplest raid system possible. It is a parallel recording of information from the main disk to the other – duplicate ones. The performance does not change in any way. It is widely used in server services, because in case of failure of one of the drives, all duplicated data remains on other media. In this case, the volume of only one hard drive will be available to you.
Let’s say you have 3 drives of 500 GB each. Out of 1500 GB, you only have 500 GB left. In general, the purpose of such systems is information reservation and cloning. It makes sense to use discs with a high speed (7200 rpm) – for example, thi
RAID 1 is often used in the corporate environment, where information loss can result in serious losses.
Advantages
High reliability
Disadvantages
High cost
RAID 10 (1 + 0)
All other types of arrays are different variations of the first two. RAID 10 – Combines the best of RAID 1 and RAID 0. You need a minimum of 4 media, and the number should always be even. With this array, you get high performance and high reliability. However, as in the case of RAID 1, you will only have access to half of the total capacity of the entire system.
Example; 4 hard drives for 1000 GB with a speed of 200 MB/s. The final speed is 400 MB / s. The total volume is 2000 GB.
Advantages
High performance
High reliability
Disadvantages
The total volume is equal to 1/2 of the total.
High cost.
RAID 5
It is very similar in its principle of working with RAID 1. Only now you need at least 3 drives, one of which will store duplicate information. In this case, you will have access to almost the entire volume in the system, except for one disk with data for recovery. In addition, performance will also increase, but not by several times, as is the case with RAID 0. The main difference between RAID 5 and RAID 10 is the level of reliability and available capacity. This array is intended for more specific tasks when a huge number of disks are assembled together.
Let’s say you have 4 disks of 2 TB each. RAID 10 will give you 4 TB of capacity, 2x the speed and the ability to fully recover information in the event of a failure of two primary media. RAID 5, in this case, will give 6 TB for your needs, slightly increased data writing speed and the ability to recover data from only one damaged hard drive. In this case, RAID 10 looks like a more attractive system than RAID 5, because for a fee of 2 TB, we get high performance and full recoverability.
But the situation changes when the number of disks becomes much larger. As we said, RAID 5 is a specific structure. If you have 10 disks of 2 TB each, then RAID 10 will only give you 10 TB that is available to you. In the case of RAID 5, this is already 18 TB (all disks are available, except for one that stores duplicated data). Here, 50% of the available volume is already too high a price for the possibility of full recovery and double speed. It is much more profitable to get a slightly increased speed, almost full volume and the ability to restore any one disk. For a common man in the street, such systems are not needed.
Advantages
Doesn’t require a lot of space for restoration Slightly increases productivity.
disadvantages
Not intended for household use Provides incomplete data redundancy Speed gain is not as big as RAID 10
There are other types of arrays, but they are all too narrowly focused and not suitable for the average user. The schemes described above are used in 90% of cases.
How to create a RAID array
There are two ways – hardware and software. In the first case, you will need several disks connected to the motherboard and a RAID controller. The RAID controller can be installed separately, or it can already be built into the motherboard itself, but the built-in ones, as a rule, have less capabilities and potential.
In the case of the software method, you will need a special installed program that simulates the operation of the controller. However, it should be understood that in this way the processor and RAM resources are affected, which negatively affects the overall performance of the PC. In addition, conflicts between the operating system and software are not uncommon. Therefore, this method should be considered solely for the purposes of experiments and tests.
In order to use the hardware method, you need to enter the operating system BIOS and set the RAID mode. After restarting the PC, you will be taken to the array setup menu. After setting more detailed settings, you can use the array like a regular disk.
Be careful, all data on disks will be erased when creating an array!
If you are faced with the trivial task of making a backup, it is not necessary to mess with RAID.
