Patent ID: 7984260
Filing Date: 2011-07-19
Classification: G06F

Abstract:
1. A storage system for receiving and processing I/O requests from a host device, comprising: a plurality of controller modules for receiving I/O requests; a plurality of physical storage devices for storing data in accordance with I/O requests; a plurality of global logical storage devices; and a plurality of local logical storage devices based on the plurality of physical storage devices, wherein each global logical storage device is a logical storage device managed by the plurality of controller modules, and correlated to any of the plurality of local logical storage devices, wherein each local logical storage device is a logical storage device managed by one of the plurality of controller modules, and wherein each controller module comprises: an inter-module connection unit connectable to one or more other controller modules among the plurality of controller modules; a storage resource that stores global device management information containing information representing whether or not a local logical storage device correlated to each global logical storage device is managed by the controller modules, and local device management information that is information relating to a local logical storage device to be managed by the controller modules among the plurality of local logical storage devices; and an access control unit that judges whether or not the local logical storage device correlated to the global logical storage device specified by an I/O request received from the host device or a first other controller module among one or more controller modules is managed by one of the controller modules based on the global device management information, accesses the local logical storage device correlated to the global logical storage device based on the local device management information when a result of the judgment is affirmative, or transfers the received I/O request to a second other controller module among the one or more other controller modules if the result of the judgment is negative, wherein each of the controller modules further comprises: a data migration control unit that controls migration of data from a first local logical storage device among the plurality of local logical storage devices correlated to a first global logical storage device among the plurality of global logical storage devices, to a second local logical storage device among the plurality of local logical storage devices correlated to a second global logical storage device among the plurality of global logical storage devices; a first data migration control unit possessed by a first controller module managing the first local logical storage device updates information relating to the first global logical storage device in the global device management information stored by the storage resource possessed by the first controller module to information representing that a local logical storage device correlated to the first global logical storage device is not managed by the first controller module; and a second data migration control unit possessed by a second controller module managing the second local logical storage device updates information relating to the first global logical storage device in the global device management information stored by the storage resource possessed by the second controller module to information representing that the first global logical storage device is correlated to the second local logical storage device managed by the second controller module, wherein cache memory that temporarily stores data to be written to the local logical storage devices or data read from the local logical storage devices is contained in the storage resource of each the storage modules, wherein the first data transfer control unit, during the data migration, reads data from the first local logical storage device, writes the read data to a first cache memory in the storage resource possessed by the first controller module, and notifies the second data transfer control unit of data location information representing the location of the written data, and wherein the second data transfer control unit, during the data migration, reads data from the location of data specified by data position information received from the first data transfer control unit, and writes the read data to the second local logical storage device.