cpqDaPhyDrvPathIndex, ranging from 0 to 3, distinguishes between multiple simultaneous access-path instances from a controller to the same physical drive, and combined with cpqDaPhyDrvPathCntlrIndex and cpqDaPhyDrvPathDrvIndex uniquely identifies one specific access path. This lets an admin tell apart the individual redundant paths, such as active versus alternate, feeding a single dual-ported drive. For example, on a drive with two redundant paths, an admin would see path index 0 and path index 1 as the two distinct routes and check each one's status independently.