Patent ID: 7093155

Claim:
An information processing system comprising: a storage having a logical unit logically assigned to a physical device; and a plurality of information processing apparatuses which are selectively connected to said storage and request data input/output from said storage, said information processing system requesting data input/output via a plurality of paths as communication channels to said logical unit, wherein each of said information processing apparatuses comprises: an error detection section which detects occurrence of an error on a path according to a result of a data input/output request; a changeover evaluation section which detects occurrence of error on a specified number of paths to determine whether or not to change an information processing apparatus connected to said storage even before occurrence of errors on all paths; and a changeover section which uses a determination result from said changeover evaluation section to change said information processing apparatus requesting data input/output to/from said logical unit, wherein said error detection section specifies an instantaneous break error resulting from a path's instantaneous break, and wherein said changeover evaluation section assigns a larger value to the number of paths used as a criterion for changing an information processing apparatus due to said instantaneous break error than a value assigned to the number of paths used as a criterion for changing an information processing apparatus due to errors other than the instantaneous break error.