Patent ID: 7356660

Claim:
A system for storing data of files comprising: a first storage system having a first logical unit configured by a plurality of first disk devices, a second logical unit configured by a plurality of second disk devices, and a first controller coupled to the plurality of first disk devices and the plurality of second disk devices, characteristics of the first logical unit being different from characteristics of the second logical unit, and a controller coupled to the first storage system, managing a first file system configured in the first logical unit and a second file system configured in the second logical unit as local file systems, and managing data objects stored in the first logical unit and the second logical unit as files, wherein the controller defines storage classes of the first logical unit and the second logical unit based on the characteristics of the first logical unit and the second logical unit, wherein based on the storage classes and a storing condition for determining a storing location of a certain file to be stored in the system, the controller determines the first logical unit as the storing location of the certain file and controls to store data of the certain file in the first logical unit, wherein when a second storage system having a third logical unit configured by a plurality of third disk devices and a second controller coupled to the plurality of third disk devices is coupled to the controller, the controller detects the second storage system and obtains characteristics information of the third logical unit, wherein the controller defines a storage class of the third logical unit based on the characteristics information of the third logical unit, wherein the controller determines whether or not a third file system is configured in the third logical unit based on the characteristic information, and wherein if the third file system is configured in the third logical unit by the second storage system, the controller manages the third file system as a remote file system, and controls a migration operation of the certain file from the first file system to the third file system based on the storage class of the third logical unit and a migration condition for the certain file.