Using storage controllers to respond to multipath input/output requests

A computer program product comprising a computer readable storage medium having program instructions embodied therewith, wherein the computer readable storage medium is not a transitory signal per se, the program instructions readable and/or executable by a first controller to cause the first controller to perform a method comprising:

• receiving, by the first controller, an input/output request along a designated communication path, wherein the designated communication path connects a host to the first controller, wherein at least a second communication path connects the host to the first controller, wherein the first controller is in communication with a second controller, the second controller being connected to the host by at least a third communication path and a fourth communication path;
• evaluating, by the first controller, a workload associated with each of the communication paths connecting the host to a respective one of the first and second controllers;
• selecting, by the first controller, one of the communication paths having a lowest workload associated therewith;
• determining, by the first controller, whether the selected communication path connects the host to the first controller;
• determining, by the first controller, whether the selected communication path is the designated communication path in response to determining that the selected communication path connects the host to the first controller;
• sending, by the first controller, a special status along the designated communication path in response to determining that the selected communication path is not the designated communication path, the special status indicating that the designated communication path was not chosen to satisfy the input/output request;
• and
• sending, by the first controller, information corresponding to the input/output request as well as a status along the selected communication path, wherein the status indicates that the selected communication path was chosen to satisfy the input/output request.

A controller-implemented method, comprising:

• receiving an input/output request along a designated communication path, wherein the designated communication path connects a host to the controller, wherein at least a second communication path connects the host to the controller, wherein the controller is in communication with a second controller, the second controller being connected to the host by at least a third communication path and a fourth communication path;
• evaluating a workload associated with each of the communication paths connecting the host to a respective one of the controller and the second controller;
• selecting one of the communication paths having a lowest workload associated therewith;
• determining whether the selected communication path connects the host to the controller;
• determining whether the selected communication path is the designated communication path in response to determining that the selected communication path connects the host to the controller;
• sending a special status along the designated communication path in response to determining that the selected communication path is not the designated communication path, the special status indicating that the designated communication path was not chosen to satisfy the input/output request;
• and
• sending information corresponding to the input/output request as well as a status along the selected communication path, wherein the status indicates that the selected communication path was chosen to satisfy the input/output request.