A storage server with three drives was reporting errors indicating the array was in degraded mode, but the stored files were still accessible. A technician went to the server room to troubleshoot the

RAID 0 provides no fault tolerance; if one drive fails, all data in the array is lost and becomes inaccessible.

RAID 1 (mirroring) requires a minimum of two drives, not three, and while it provides fault tolerance, the question describes a three-drive array and degraded mode with accessible files, which points more directly to RAID 5's parity scheme.

RAID 5 requires a minimum of three drives and uses striping with distributed parity. This configuration allows the array to continue operating in a "degraded" state, with all data still accessible, even if one drive fails, because the missing data can be reconstructed using the parity information.

RAID 10 (or RAID 1+0) requires a minimum of four drives, as it is a stripe of mirrors, and the scenario describes a three-drive array.