When transferring data between the host server and storage, the SAN uses a technique known as multipathing. Multipathing allows you to have more than one physical path from the ESX/ESXi host to a LUN on a storage system.

Generally, a single path from a host to a LUN consists of an iSCSI adapter or NIC, switch ports, connecting cables, and the storage controller port. If any component of the path fails, the host selects another available path for I/O. The process of detecting a failed path and switching to another is called path failover.