COMPUTER SYSTEM PREVENTING STORAGE OF DUPLICATE FILES

• US 20080244199A1
• Filed: 01/11/2008
• Published: 10/02/2008
• Est. Priority Date: 03/27/2007
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Tabuchi, Hideo, NAKAMURA, Yasuaki
• Granted Patent: US 7,900,000 B2
• Time in Patent Office: Days
• US Class Current: 711/156
• CPC Class Codes: G06F 16/1748 De-duplication implemented within the file system, e.g. based on file segments de-duplication techniques in storage systems for the management of data blocks G06F3/0641
• CPC Class Codes: G06F 16/1824 implemented using Network-attached Storage [NAS] architecture distributed or networked storage systems G06F3/067; protocols for distributed storage of data in a network H04L67/1097

Abstract

A plurality of contents intrinsic values that are values intrinsic to respective contents of a plurality of files stored in one or more first storage devices are calculated. Whether two or more identical contents intrinsic values are contained among the plurality of contents intrinsic values is determined. When two or more identical contents intrinsic values are present, an access destination of a first file corresponding to a first contents intrinsic value from among these two or more contents intrinsic values is changed to a position having stored therein a second file corresponding to a second contents intrinsic value from among these two or more contents intrinsic values.

Claims

1. A computer system comprising:

a computer; and

a first storage system having one or more first logical storage devices where a plurality of files are stored, wherein

said computer comprises;

an intrinsic value calculation unit that calculates a plurality of content intrinsic values that are values intrinsic to contents of a plurality of files; and

an intrinsic value transmission unit that transmits a plurality of content intrinsic values corresponding respectively to said plurality of files to said first storage system, and

said first storage system comprises;

a duplication determination unit that determines whether two or more identical contents intrinsic values are contained in said plurality of contents intrinsic values; and

a change control unit that changes an access destination of a first file corresponding to a first contents intrinsic value from among these two or more contents intrinsic values to a position having stored therein a second file corresponding to a second contents intrinsic value from among these two or more contents intrinsic values when there are said two or more identical contents intrinsic values.

2. The computer system according to claim 1, wherein

said intrinsic value calculation unit calculates said plurality of contents intrinsic values when said plurality of files are taken as archive objects.

3. The computer system according to claim 2, wherein

said intrinsic value calculation unit prohibits said first storage system from updating said one or more first logical storage devices where said plurality of files are stored when said plurality of files are taken as archive objects.

4. The computer system according to claim 1, wherein

there are a plurality of storage period limits that are respectively associated with said plurality of contents intrinsic values, and

said change control unit changes an access destination of said first file corresponding to said first storage period limit to a position having stored therein said second file corresponding to a second storage period limit that is longer than the first storage period unit, from among two or more storage period limits respectively corresponding to said two or more identical contents intrinsic values.

5. The computer system according to claim 1, wherein

a second storage system comprising one or more second logical storage devices is connected to said first storage system,

said first storage system further comprises:

one or more virtual logical storage devices respectively associated with said one or more second logical storage devices; and

a migration execution unit that writes a body of each file stored in said one or more first logical storage devices to said one or more second logical storage devices via said one or more virtual logical storage devices of a migration destination, and wherein

said migration execution unit does not write a body of said first file into any of said one or more second logical storage devices and writes a body of said second file into any of said one or more second logical storage devices from among two or more files respectively corresponding to said two or more identical contents intrinsic values, and

said change control unit changes an access destination of said first file to a position where a body of said second file has been written.

6. The computer system according to claim 5, wherein

before said migration is started, none of said one or more first logical storage devices that store said plurality of files can be updated, and after said migration is completed, each of said one or more virtual logical storage devices can be updated, but none of said plurality of files that have become the object of said migration can be updated.

7. The computer system according to claim 5, wherein

there are a plurality of storage period limits respectively associated with said plurality of contents intrinsic values, and

said change control unit changes an access destination of said first file corresponding to said first storage period limit to a position having stored therein said second file corresponding to a second storage period limit that is longer than the first storage period unit, from among two or more storage period limits respectively corresponding to said two or more identical contents intrinsic values.

8. The computer system according to claim 7, wherein said change control unit controls the change of access destination based on a device characteristic of said one or more second logical storage devices.

9. The computer system according to claim 7, wherein

there are a plurality of storage period limits respectively associated with said plurality of contents intrinsic values, and

when a migration destination of a first file corresponding to the longest storage period limit and a second file that is another file, from among two or more files respectively corresponding to said two or more identical contents intrinsic values, is a first virtual logical storage device corresponding to a first second logical storage device having a device characteristic of a first type, and a migration destination of a third file with a storage period limit longer than the storage period limit of said second file is a second virtual logical storage device corresponding to a second second logical storage device having a device characteristic of a second type that is superior to said device characteristic of the first type, said change control unit changes an access destination of said second file to a position having stored therein a body of said third file, and

said migration execution unit writes a body of said first file to said first second logical storage device via said first virtual logical storage device, does not write a body of said second file into said first second logical storage device, and writes a body of said third file into said second second logical storage device via said second virtual logical storage device.

10. The computer system according to claim 9, wherein

said change control unit executes at least one operation of the following (1) and (2):

(1) changing an access destination of said first file to a position where a body of said third file is stored, when reading of a body of said first file from said first second logical storage device is impossible; and

(2) changing an access destination of said third file to a position where a body of said first file is stored when reading of a body of said third file from said second second logical storage device is impossible.

11. The computer system according to claim 1, wherein

said computer further comprises a storage area and a completeness check unit,

said first storage system further comprises a storage area that stores a plurality of contents intrinsic values received from said computer,

said intrinsic value calculation unit stores said plurality of contents intrinsic values in the storage area of said computer, and

said completeness check unit compares a contents intrinsic value from among said plurality of contents intrinsic values that are stored in the storage area of said computer, this contents intrinsic value corresponding to the file selected from said plurality of files, with a contents intrinsic value corresponding to said selected file that has been stored in the storage area of said first storage system.

12. The computer system according to claim 1, wherein

said first storage system further comprises a saved capacity notification unit, and

said saved capacity notification unit calculates a storage capacity saved by changing the access destination of said first file and sends information indicating this storage capacity to said computer.

13. The computer system according to claim 1, wherein

said change control unit changes the access destination by updating a change management table having a plurality of records respectively corresponding to said plurality of files,

a field having recorded therein a record ID, position information of the file thereof, and a record ID of a reference destination is present in one said record corresponding to one file;

and

said change control unit updates the record ID of said reference destination to a record ID on the second record corresponding to said second file in a first record corresponding to said first file.

14. The computer system according to claim 13, wherein

a second storage system comprising one or more second logical storage devices is connected to said first storage system,

said first storage system comprises:

one or more virtual logical storage devices respectively associated with said one or more second logical storage devices; and

a migration execution unit that writes a body of each file stored in said one or more first logical storage devices to said one or more second logical storage devices via said one or more virtual logical storage devices of a migration destination; and

an access control unit, and wherein

a storage period limit of a file and an access attribution of a file are recorded in one record of said change management table,

said intrinsic value calculation unit prohibits said first storage system from updating said one or more first logical storage devices where said plurality of files are stored when said plurality of files are taken as archive objects,

said migration execution unit does not write a body of said first file into any of said one or more second logical storage devices and writes a body of said second file into any of said one or more second logical storage devices from among two or more files respectively corresponding to said two or more identical contents intrinsic values, and

said change control unit updates a reference destination record ID on said second record of said second file corresponding to a second storage period limit that is longer than a first storage period limit, from among two or more storage period limits respectively corresponding to said two or more identical contents intrinsic values, to an ID on said first record of said first file corresponding to said first storage period limit and sets an access attribution on said first and second records to Read Only; and

even if receiving a write access designating a position shown by a position information on said first and second records, said access control unit does not execute writing to this position.

15. A storage system comprising:

one or more first logical storage devices where a plurality of files are stored;

a duplication determination unit that determines whether two or more identical contents intrinsic values are contained in a plurality of contents intrinsic values that are values intrinsic to respective contents of said plurality of files; and

a change control unit that changes an access destination of a first file corresponding to a first contents intrinsic value from among these two or more contents intrinsic values to a position having stored therein a second file corresponding to a second contents intrinsic value from among these two or more contents intrinsic values, when there are said two or more identical contents intrinsic values.

16. The storage system according to claim 15, which is connected to an external storage system having one or more second logical storage devices, and which further comprises:

one or more virtual logical storage devices respectively associated with said one or more second logical storage devices; and

a migration execution unit that writes a body of each file stored in said one or more first logical storage devices to said one or more second logical storage devices via said one or more virtual logical storage devices of a migration destination, wherein

said migration execution unit does not write a body of said first file into any of said one or more second logical storage devices and writes a body of said second file into any of said one or more second logical storage devices from among two or more files respectively corresponding to said two or more identical contents intrinsic values, and

said change control unit sets an access destination of said first file to a position where a body of said second file has been written.

17. The storage system according to claim 16, wherein

there are a plurality of storage period limits that are respectively associated with said plurality of contents intrinsic values, and

said change control unit changes an access destination of said first file corresponding to said first storage period limit to a position having stored therein said second file corresponding to a second storage period limit that is longer than the first storage period limit, from among two or more storage period limits respectively corresponding to said two or more identical contents intrinsic values.

18. A storage control method comprising the steps of:

calculating a plurality of contents intrinsic values that are values intrinsic to respective contents of a plurality of files stored in one or more first storage devices;

determining whether two or more identical contents intrinsic values are contained in said plurality of contents intrinsic values; and

changing, when two or more identical contents intrinsic values are present, an access destination of a first file corresponding to a first contents intrinsic value from among these two or more contents intrinsic values to a position having stored therein a second file corresponding to a second contents intrinsic value from among these two or more contents intrinsic values.