Originally defined as Redundant Array of Inexpensive Disks, RAID – now short for Redundant Array of Independent Disks – stores the same data in different places on multiple hard disks. RAID differs from earlier storage devices that stored data on a single disk. RAID stores data redundantly in a balanced way to improve performance, as well as increase fault tolerance so that the array and its data are still usable if a drive fails. Though RAID uses multiple disks, it appears as a single device to an operating system, which provides increased storage capacity. RAID has levels, which signify how the drives are arranged and how the data is distributed across them. The data distribution layout is identified by the word “RAID” and followed by a number, such as RAID 0 or RAID 5. Each RAID level has a different balance of performance, capacity and fault tolerance. RAID 0, RAID 1 and RAID 5 are the most commonly used RAID levels for private consumers and small businesses. These levels, along with levels 2 through 6 are considered standard levels. You may also encounter non-standard levels and nested levels, such as level 0+1, level 7 or level 1E. The redundancy of RAID is essential for businesses, as drive failures do occur. However, while RAID can protect against hardware failure, it does not protect against data loss caused by malware, cybercrime, power outages or natural disasters. And, like all technology, the RAID system itself is susceptible to corruption, malfunction, damage and failure. This is why backing up your data on a separate storage system is so essential.