Patent ID: 7606871
Filing Date: 2009-10-20
Classification: G06F,Y10S

Abstract:
1. A method for virtualizing a plurality of network storages connected to a network into a virtualized network storage system which can be accessed from a client as a single network storage, the method comprising steps of: predetermining a group map function which correlates a file to only one file group based on a hash function of a file identifier of the file by using a file inode number I as a search key and a hash value given by the hash function G=Hash (I) which constitutes a file group identifier G; performing said group map function for at least said file; creating a file group allocation table which records mutual correlation between each of a plurality of file groups and a destination network storage to store files belonging to a corresponding one of the file groups according to said group map function; storing each of the grouped files into said destination network storage, respectively; when a new network storage to become a new destination network storage is being added to said virtualized network storage system, issuing an available remaining capacity acquisition request to each existing destination network storage; identifying a destination network storage which has a smallest available remaining capacity among the existing destination network storages; moving files belonging to only one of file groups maintained in the identified destination network storage to said new network storage; and repeating the steps of issuing, identifying and moving until a difference between an available remaining capacity of said new network storage and said smallest available remaining capacity becomes lower than a threshold.