Identification and use of preferred path groups in host computer based on differential performance

Abstract

A host computer accesses a federated storage volume at first and second frames (physical storage assemblies). The host identifies a preferred frame by (1) obtaining representative values of a performance metric for sets of paths to the volume, each set associated with a different frame, and (2) selecting the frame associated with the path set having the best representative value. In one example a response latency is used to detect different distances to the host and identify the closer frame, which will be preferred. Operating modes of the paths for non-preferred frames are set to 'standby'. During subsequent operation using path selection to send storage operations to the volume, the host selects among paths in an 'active' operating mode so as to access the volume at the preferred frame under normal operating condition. Standby paths are reserved for less normal operating conditions, such as when no active path is available.