multipathing (SAN multipathing)

Multipathing, also called SAN multipathing or I/O multipathing, is the establishment of multiple physical routes between a server and the storage device that supports it. 

In storage networking, the physical path between a server and the storage device that supports it can sometimes fail. When there's only one physical path between the two devices, there is a single point of failure (SPoF), which can be a problem if a cable breaks or someone accidentally unplugs the wrong cable. Because SAN multipathing establishes multiple routes between the hardware, however, if someone accidentally unplugged the wrong cable and one path failed, I/O would simply be routed through another path. 

In addition to being a useful failover tool, multipathing can assist with load balancing, spreading I/O across multiple paths to reduce latency.