Patent ID: 8316065

Claim:
A data migration system, comprising: a data migration device that includes a processor; a first file server that includes a processor, which is coupled to said data migration device; a second file server that includes a processor, which is coupled to said data migration device; a first storage device which is coupled to said first file server; a second storage device which is coupled to said second file server; and a third storage device which is coupled to said second file server; wherein: said first file server creates a first file system upon said first storage device; said first file system has a first file; said second file server creates a second file system upon said second storage device and a third file system upon said third storage device; said first file server creates a tiered structure in which said second file system, and said third file system, are consolidated virtually; when migrating said first file, said second file server: receives file creation instruction from said data migration device; creates a second file where a first inode number is imparted to said second file system, wherein the second file is in a temporary state in a pseudo file system; receives attribute information of said first file; when said second file is determined to be in the temporary state in the pseudo file system as determined by referring to an object management table, refers to said attribute information of said first file to assign attribute information to said second file; determines which file system said first file is migrated to, said second file system or said third file system, when migration to said third file system is determined: creates a third file where a second inode number signifying said third file being a real file in a real file system is imparted to said third file system; receives and stores data of said first file as data of said third file; and sets attribute information of said second file to correspond to said attribute information of said third file, wherein said object management table includes a plurality of entries each assigning a pseudo inode number of a virtual file in a pseudo file system with a real inode number of a real file in a real file system.