A disk array is a data storage system that uses multiple disk drives to store data. Disk arrays are typically used in enterprise applications where large amounts of data must be stored securely and quickly. Disk arrays can be used to store data on a variety of media, including hard drives, SSDs, and optical drives. Disk arrays usually have a controller that manages the process of storing and retrieving data. The controller usually has its own cache memory and processing power, which helps improve the performance of the disk array. Disk arrays can be configured in many different ways, depending on the needs of the application. For example, they can be configured as a RAID (Redundant Array of Inexpensive Disks) system, which provides fault tolerance by using multiple copies of data. Disk arrays can also be used to create a storage area network (SAN), which is a high-speed network connecting devices that need to share data.