Asymmetric Logical Unit Access (ALUA) is a SCSI standard that provides multiple paths to storage devices, enhancing fault tolerance and load balancing in storage area networks (SAN). ONTAP, the storage operating system by NetApp, supports ALUA on SAN protocols. The protocols supported by ALUA in the context of an ONTAP cluster are iSCSI and FCP (Fibre Channel Protocol). ALUA is typically used in SAN environments, and iSCSI and FCP are both traditional SAN protocols. NVMe, on the other hand, uses ANA (Asymmetric Namespace Access) instead of ALUA, and NFS is a file-based protocol rather than a typical SAN protocol.