Patent ID: 7836204
Filing Date: 2010-11-16
Classification: G06F,H04L

Abstract:
1. An apparatus to access a path through a storage controller, the apparatus comprising: a plurality of host ports each configured to communicate with a host via a respective one of a plurality of host communication channels between the host and the host ports, wherein input/output (I/O) requests from the host are directed through a selected one of the plurality of host communication channels; a request module configured to receive a path identification request from the host to identify a plurality of paths from the host to a selected control unit image of a plurality of control unit images of the storage controller, each path comprising one of the plurality of host communication channels and at least one of a plurality of redundant interconnection modules of the storage controller, wherein a first path of the plurality of paths comprises a first host communication channel of the plurality of host communication channels and a first redundant interconnection module of the plurality of redundant interconnection modules, the first redundant interconnection module comprising the selected control unit image, and a second path of the plurality of paths comprises a second host communication channel of the plurality of host communication channels, the first redundant interconnection module, a second redundant interconnection module of the plurality of redundant interconnection modules, and an internal communication channel of the storage controller between the first and second redundant interconnection modules, the internal communication channel facilitating the communication of I/O requests from the host between the first and second redundant interconnection modules, and wherein each of the plurality of control unit images comprises a virtual module emulated by the storage controller, each control unit image comprising a management group of at least one logical device, the at least one logical device being configured to emulate a storage device; a response module configured to report the first and second paths, the status of the first and second paths relative to the control unit image, and an identifier of the first and second paths to the host, the response module being configured to designate the first path as a preferred path and the second path as a non-preferred path, wherein the designation of the first and second paths as one of preferred and non-preferred is based on which of the first and second redundant interconnection modules comprises the selected control unit image and which of the first and second host communication channels places the host in more direct communication with the selected control unit image; and a connection module configured to direct I/O requests from the host to the selected control unit image through the preferred path if the first redundant interconnection module is operable and through the non-preferred path if the first redundant interconnection module is inoperable.