Abstract: Disclosed is a system, method, and program for analyzing proposed interface ports to a device. Failure boundary data is read from the device indicating at least one failure boundary of a proposed interface to the device and a mask is accessed from the device. The accessed mask is applied to the failure boundary data for the proposed interface and existing interfaces to determine at least one failure boundary for the proposed interface and existing interfaces. A determination is made of a number of single points of failure for the proposed interface port from the determined failure boundaries the proposed interface has in common with interface ports currently used to access the device. A further determination is made of a relative availability rating based on the number of single points of failure for each proposed interface port.

Abstract: Disclosed is a method, system, program, and data structure for selecting a path to one of at least two controllers. Each controller is capable of providing access to storage areas, such as Logical Unit Numbers (LUNs). Path information is received from the controllers indicating a preferred controller to use to access each storage area. An input/output (I/O) command directed to a target storage area is processed and the I/O command is directed to the controller indicated in the path information as the preferred controller for the target storage area. The controller receiving the I/O command executes the I/O command against the target storage area. The path information to the storage controllers providing access to the storage areas is encoded with information designating one controller as the preferred controller and another as a non-preferred controller. The encoded path information is returned to a requesting computer.