Patent ID: 7603507
Filing Date: 2009-10-13
Classification: G06F

Abstract:
1. A storage system, comprising: a first storage device having a virtual volume used by a host; and a second storage device having an actual volume associated with the virtual volume and connected to the first storage device via a plurality of communications paths, each communications path being in a usable or unusable state, wherein the first storage device comprises: a mapping management section having mapping information representing connections between the virtual volume and the actual volume by communications paths, and mapping the actual volume as the data storage destination volume of the virtual volume, and a control section, which includes the mapping management section, for processing access requests from the host to the virtual volume based on the mapping information between the virtual volume and the actual volume managed by the mapping management section, wherein the control section selects at least one of the communications paths for processing of the access requests based on the mapping information, wherein priority of each of the communications paths is preset, wherein the control section selects at least one of the usable communications paths based on the priority and uses the communications path, wherein the control section further comprises: a failure detector to detect whether or not a failure has occurred in any of the communications paths, wherein at least one of the usable communications paths is selected and used when the failure detector detects occurrence of a failure in a communications path in use, wherein the mapping information managed by the mapping management section stores in corresponding relations at least: virtual volume identification information for identification of the virtual volume, actual volume identification information for identification of the actual volume, information on each path to access the actual volume from the virtual volume using the communications paths, state information to indicate whether each communications path is in a usable or unusable state, and priority information including a different priority assigned to each of the communications paths, said priority information, by use of different priorities assigned to the communications paths, indicates the order of use of each of the usable communications paths when replacing a failed communications path, and wherein upon detection of a failure of one of the communications paths, said control section selects one of the usable communications paths having the highest priority to replace the failed communications path according to the priority information of the mapping information.