Patent ID: 8694602

Claim:
A storage apparatus comprising: a storage controller comprising a processor configured to convert data which is sent to or received from a computer via a network, based on a determination whether the processor executes a first data conversion processing or not; a plurality of storage devices, each of the storage devices comprising a storage medium and a device controller configured to convert data based on a command from the storage controller, for instructing to execute the first data conversion processing or a second data conversion processing; wherein the storage controller is configured to manage a load of the storage controller by associating it with one or more logical units which are access targets of the computer in executing the data conversion processing on a cache memory; and when the storage controller receives an access request from the computer, the storage controller is configured to judge whether the load of the storage controller exceeds a threshold or not; and when the storage controller determines that the load of the storage controller exceeds the threshold, the storage controller is configured to execute, on the cache memory, the first data conversion processing for converting data relating to the logical units, which are the access targets of the computer, from a first block size into a second block size or the second data conversion processing for converting the data from the second block size into the first block size; and when the storage controller determines that the load of the storage controller does not exceed the threshold, the storage controller gives a command to the device controller of one of the plurality of storage devices to execute the first data conversion processing or the second data conversion processing; and wherein the device controller executes the first data conversion processing or the second data conversion processing based on the command from the storage controller, wherein the storage controller is configured to manage the load of the storage controller by comparing it with a load on the device controller and selecting the storage controller or the device controller to execute the data conversion based on which of the storage controller or the device controller bears the lower load.