RAID stands for "redundant array of independent disks" or "redundant array of inexpensive disks". It is a data storage virtualization technology that combines multiple physical disk drive components into one or more logical units for the purposes of data redundancy, performance improvement, or both. RAID arrays appear to the operating system as a single logical drive. Data is distributed across the drives in one of several ways, referred to as RAID levels, depending on the required level of redundancy and performance. The different RAID levels provide a different balance among the key goals: reliability, availability, performance, and capacity. Here are some of the most popular RAID configurations:
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RAID 0: This level offers the fastest read/write speeds and maximum availability of raw storage capacity. However, it does not provide any data redundancy.
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RAID 1: This level provides data redundancy by mirroring data on one drive across other drives.
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RAID 5: This level balances performance and redundancy by splitting data into groups across all available drives and creating distributed parity, where data calculations are stored across the drives so that any one drive may fail, and the data or parity on the other drives can reconstitute what was lost on the failed drive.
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RAID 10: This level combines RAID 1 and RAID 0 to provide both data redundancy and performance improvement.
There are other RAID levels as well, such as RAID 2, RAID 3, RAID 4, RAID 6, RAID 7, and Adaptive RAID. RAID can be managed using a RAID controller, which is a device used to manage hard disk drives in a storage array. Using a RAID controller can improve performance and help protect data in case of a crash.
