Patent ID: 8819307

Claim:
A method of operating a host computer having access to a storage volume via two or more frames of a storage system, each frame being a uniquely identified manufactured assembly providing access to associated physical storage, comprising: identifying one of the frames as a preferred frame by: (1) obtaining representative values of a performance metric for respective sets of paths to the volume, each set of paths being associated with a respective different one of the frames; and (2) selecting as the preferred frame the frame associated with the set of paths having a best representative value of the performance metric, each frame that is not selected being a non-preferred frame; for subsequent storage read and write operations in which path selection is used to send storage read and write operations to the volume via different paths, selecting from among paths associated with the preferred frame so as to access the volume under normal operating conditions at the preferred frame rather than at a non-preferred frame, the paths associated with the non-preferred frame being reserved for use under less normal operating conditions in which no active path is available or otherwise suitable for use; wherein the two or more frames of the storage system include a first data storage array and a second data storage array; wherein multiple first paths connect the host computer to the first data storage array; wherein multiple second paths connect the host computer to the second data storage array; wherein the performance metric is a latency measure; wherein selecting, as the preferred frame, the frame associated with the set of paths having the best representative value of the performance metric includes: choosing the first data storage array as the preferred frame over the second data storage array due to the first paths providing lower latency than the second paths, the second data storage array being a non-preferred frame; wherein selecting from among the paths associated with the preferred frame includes: after selecting the frame associated with the set of paths having the best representative value of the performance metric as the preferred frame, (i) selecting a single first path of the multiple first paths connecting the host computer to the first data storage array in response to an input/output command, and (ii) accessing the volume through the selected single first path to process the input/output command; and wherein an inter-frame communication link connects the first data storage array and the second data storage array together; and wherein the method further comprises: providing access to any content of the volume through only one of the first paths due to inter-frame access via the inter-frame communication link.