![]() ![]() In a RAID 0 setup, the total storage capacity is the sum of all the disks used. For scenarios where you only care about performance, like gaming, RAID 0 can be useful. As the risk of failure is high, it isn’t used very often, particularly with a large number of disks, as the chance of failure would be even higher. But by the same token, it’s also much more prone to failure, as any drive failing would mean that all the data is lost.Īs RAID 0 provides no redundancy, some argue if it should even be called RAID. As the files are spread across multiple disks, the available throughput is multiplied as well. RAID 0 uses striping across atleast two disks. The RAID levels have evolved throughout the years, but the currently accepted standard, as maintained by SNIA, categorizes RAID 0 – 6 as the standard levels. Generally, RAID 0 – 4 can be managed with software controllers, while RAID 5 and higher levels require a physical RAID controller. However, as software controllers are dependent on the host machine for resources, the RAID performance boost is impacted as well. Physical RAID controllers can be pricy, while software controllers are free or affordable. The RAID array can be managed either by a dedicated RAID controller, software-based implementations (md, ZFS, etc.), or firmware and driver-based implementations. Generally, basic XOR is performed on the disks’ data to calculate the parity data, but certain RAID levels like RAID 2 or RAID 6 use dedicated parities, which we’ve talked about further in the article.įinally, there’s the matter of RAID implementation. Parity data is either stored on a dedicated disk or spread out across all the disks, and when any disk in the array fails, you can swap it out for a fresh disk and use the parity data and data from the other disks to rebuild the lost data. Parity is an error protection technique commonly used to provide fault tolerance and achieve redundancy. This makes the data on one disk redundant, but it’s intended as this allows data to be recovered in case one of the disks in the array fails. Mirroring is self-explanatory – the data from one disk is copied onto another. By concurrently accessing the data spread across multiple disks, you get to utilize the combined data throughput, which basically leads to improved performance. ![]() Depending on the RAID level, one or any combination of these techniques could be used.ĭata striping is the process of splitting consecutive segments of logically sequential data on different disks. ![]() We’ll talk about all these in further detail later, but for now, let’s just end it with a brief introduction.Īs for how RAID actually works, it implements techniques like data striping, disk mirroring, and parity. The Standard RAID Levels are RAID 0 – RAID 6, but there are numerous other levels of RAID that fall under categories like Nested RAID and Non-Standard RAID. Some are designed for one exclusive purpose, while others offer the best of both worlds. The degree to which the array focuses on redundancy or performance is dependent on the type of RAID used, typically referred to as RAID levels. Of course, this is only a broad description. Similarly, combining the specs of multiple disks provides significant performance boosts for I/O operations. Generally speaking, in a RAID setup, data is stored across multiple disks, with the primary objective of data redundancy and/or performance improvement.ĭata redundancy increases reliability by acting as a safety net against disk failure. RAID is a storage technology used to configure multiple physical disks as a single logical disk called a Logical Unit Number (LUN). ![]()
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