RAID combines multiple drives, but its behavior depends on the RAID level and configuration. Some configurations provide redundancy or improve performance; RAID is not a substitute for a separate backup. Data may become inaccessible after drive failures, controller or configuration problems, an interrupted or incorrect rebuild, or changes to drive order. The correct recovery approach depends on the array layout, member drives, controller, and the current state of the data. If an array has failed, avoid initializing it, rebuilding it, or running repair utilities until the configuration and risks have been assessed.