 Hello everybody! In today's video, we'll discuss RAID system or arrays, what they are like, why people use them, and how to build such a system. Every year, computers' hardware is becoming more and more efficient and powerful. Central processors are developing more queries and threads, while effective frequencies of graphical cards are getting higher and higher. The typical speed of hard disks has long stopped at 7 to 200 rpm. Despite widespread advance of their even faster successors, SSDs, the new disk type has a relatively lower resource potential, and its reliability leaves much to be desired. That is why some users prefer the so-called RAID arrays or systems, which can increase read and write speeds almost twofold. There are various RAID times out there, some of them focusing on a speed boost and others improving reliability of data storage. In a few minutes, I'll tell you about all known RAID times and explain which are perfect for ordinary users and which are better suited for working with server equipment. You will learn about the reasons to have such arrays, how to build them, and what is required for this purpose. In our channel and blog, you will find solutions to any problem, from installing an operating system or configuring it to fixing possible bugs and errors or optimizing mobile gadgets. Our specialists will answer any questions you ask in your comments under the videos or articles. RAID is the abbreviation for redundant array of independent disks. This is a data storage virtualization technology that combines multiple physical disk drives into one logical unit for the purpose of data redundancy, performance improvement or those. To build the RAID system, you need at least two disks, but this number may vary depending on the type and purpose of the RAID array. This disk almost every decent motherboard comes with out-of-the-box support for SATA RAID. So let's have a closer look at RAID types. The first type is RAID 0. It is based on the principle of data striping. Data is split into blocks of similar lengths that get written across all the drives in the array. The main purpose of such system is to achieve actual disk performance to fault or even more. Wealthful disk capacity of all disks within the system is available. In simpler terms, it's like combining two or more disks into one big drive. The number of disks in a RAID 0 array is unlimited. However, if the disks are of different speed, the data exchange rate for such array will be determined by its slowest disk. In RAID 0, you can combine disks of any capacity. For example, a 500-gigabyte drive can be arranged to work with one terabyte or two terabyte drive and so on. For RAID 0, you need at least two disks. And here are the advantages of this array. Suppose you have two disks, each having the capacity of 500 gigabytes and the right speed of 100 megabyte per second. When combined into a RAID 0 system, you get one terabyte of space and a right speed storing to 200 megabytes per second. Such an impressive performance boost is possible due to distribution of data handling tasks between the two disks. In this array type, disks of different capacity and speed can be used, and in the end, their space and right speeds will be summed up. This array type is mostly used for storing temporary files. On the other hand, there is no point in storing a database inside a RAID 0 system, because even if one of the disks fails, the entire array is down. And you're going to lose all the information. It happens because data is written in turns to each of the disks, so a large file may be spread over the two or more disks you have combined into the system. Hence, RAID 0 has nothing to offer in terms of fault tolerance or failure protection. If you are running a system based on three or four disks and one of them fails, all the data will be lost. Summing up, enjoy the high speed, but remember to backup your data very often. Another type is RAID 1, which uses the principle of data mirroring. Data is written in parallel to the main or data drive and a mirror drive. In other words, data is written to the main disk and copied to the mirror disk. Each pattern of disk usage doesn't affect their performance at all, but only half of the total disk capacity is available. This array type is widely used in servers, because even if one of the drives fails, all copied data is safely stored in other drives, which act as backup storage. Such systems are meant for storing data backups and cloning critical information. Arrays of this type are quite reliable and can operate as long as there is at least one healthy disk in the system. The most serious disadvantage of RAID 1 is that you can use the capacity of one disk only, while you actually have two or more of them. Generally speaking, all other RAID times are on the variations of the first two kinds – 1 and 0. RAID 10 is a combination of RAID 0 and RAID 1. Data is written in parallel to two drives, while copies of such data are written to the other two drives. Such approach offers a performance boost and improved security for data storage. To build this type of array, you need at least four disks. In the end, you'll get double read and write speed if compared to single-disk figures, but only two disks out of four are actually available for storing data. Even if two disks fail at the same time, your information will not be lost. RAID 2, RAID 3 and RAID 4 are quite rare and less popular, as they make use of Hammond code for error correction, striping data at the bit rather than the block level and check sounds. In RAID 2, information is spread across data drives, just as in RAID 0. That is, it is divided into small blocks according to the number of drives. The remaining drives are designed to store ECC or error correction code data, which could be used for recovering information should any of the data drives fail. A prominent advantage of this RAID type is extremely high data transfer rates as compared to results achieved via single-disk. This RAID type is hardly popular in home systems due to the number of hard disks required. For example, in an array made of seven drives, only four of them can be used for data storage. As the chart shows, redundancy will drop as the number of drives grows. The main advantage of RAID 2 is the possibility to implement on-the-fly data error correction without sacrificing the speed of data exchange between the disk array and the CPU. Talking of RAID 3 and RAID 4, these two types are very similar in terms of architecture. Both require several drives to store data, and one of the drives is used exclusively as a dedicated parity disk. That is, it stores checksums needed for data recovery if a drive fails. To build RAID 3 and RAID 4, you need at least three hard disks. Unlike RAID 2, on-the-fly data recovery is impossible. Information can only be recovered after you replace the faulty drive, and it takes some time to complete. The major difference between RAID 3 and RAID 4 lies in the level of data striping. RAID 3 consists of byte-level striping with dedicated parity, which suggests a considerable slowdown in reading, writing large numbers of small files. On the contrary, RAID 4 consists of block-level striping with a dedicated parity disk, and every block is no bigger than a disk factor. As a result of its layout, RAID 4 provides good performance when dealing with small files which could be of critical importance for personal computers. This is why RAID 4 is more popular. A considerable downside for these two array types is the high workload on the parity disk, the one that stores checksums, which reduces its lifespan effectively. Another array type is RAID 5. It uses the principle similar to that of RAID 1. The biggest difference is that RAID 5 needs at least three drives, and one of them is used to store copied information. In this case, you will be able to use almost all disk space within the system except for the one disk used to store recovery data. In addition, you will get a performance boost, but don't expect it to be as impressive as in the case with RAID 0. This array type is best suited for specific tasks that involve large groups of hard drives. Suppose you have four disks to terabytes each. With RAID 10, you get disk capacity of 4 terabytes, double data read and write speed, and the opportunity to completely recover all the information even if two main drives fail at the same time. In the same scenario, RAID 5 will offer you 6 terabytes of disk space, a slight increase in write speed, and the opportunity to recover data from one damaged disk only. In this line, RAID 10 looks more attractive than RAID 5. Parallel to the small feat of two terabytes, you get high performance and fast recovery options. However, things do change a lot when you are going to use disks in great numbers. If you have 10 drives two terabytes each, with RAID 10 you only work with the 10 terabytes of space you can access. On the contrary, it's the huge 18 terabytes you can enjoy with RAID 5. All disks are available except the one that has to be sacrificed to copy data. As you can see, being able to use only 50% of the physical space seems too high a promise to pay for double speed and full recovery prospects. To many users, it looks more appealing to get a small performance bonus, lose only a small share of disk space and be able to recover data from any disk, provided that only one of them fails. Building RAID 6 array allows to solve this problem to a great extent. As array type allocates total volume of two disks for storing checksums, which are spread over different disks in a cyclic and regular way. Instead of one checksum, two checksums are calculated, which ensures data integrity even if two drives within one array fail at the same time. RAID 6 advantages are higher data protection and less performance loss, as compared to RAID 5, in case of recovering data after the faulted drive is replaced. The disadvantage of RAID 6 is a 10% decrease in overall data transfer rate caused by the growing amount of calculations required to generate the checksums and the increasing volumes of data to be read and written. So how do you go about creating a RAID system? There are two main ways – hardware and software. In the first case, you will need several hard disks connected to the motherboard plus a RAID controller, unless your motherboard already supports RAID. The next step is to enable RAID in BIOS settings. When you restart the computer, there should be a chart with more detailed RAID settings. If it doesn't show up, you may need to restart again and try pressing the key shortcut Ctrl plus I when the computer starts booting. If you use an external controller, it's likely you will have to press F2 button. In the chart, choose Configure and select the level you need. After the RAID array is created in BIOS, boot the computer, open disk management and format the unallocated space. This is the RAID array you have just created. For a software RAID, you don't need to enable or disable anything in BIOS. In fact, you don't even need your motherboard to support RAID. As we have mentioned before, this technology can be implemented with the CPU and the integrated operating system tools. This way, you can create a RAID 1 system. First click on the Start button and select Disk Management. Then click on any of the drives you have prepared for building a RAID system and select New Mirrored Volume. In the next window, select the disk which you want to mirror the other disk, assign the drive letter and format this new partition. In Disk Management, mirrored volumes are highlighted in the same color and have the same drive letter. Files are copied to both volumes. One first to one volume and then to the other. In this PC window, the array will be displayed as one partition. If any of the disks within the system fails, you will see an error saying failed redundancy, while all data in the second disk will be intact. However, it doesn't mean you should allow a bit of carelessness. When you create a RAID system, all data on the disk involved into the process will be erased. So before you start, make sure that important data is backed up elsewhere. And that is all for now. Hopefully this video was useful. Remember to click the Like button and subscribe to our channel. Hit the bell button to receive notifications and never miss new videos. Leave comments to ask questions. Thank you for watching. Good luck.