Storage Controller and Duplicated Data Detection Method Using Storage Controller

• US 20090254507A1
• Filed: 06/10/2008
• Published: 10/08/2009
• Est. Priority Date: 04/02/2008
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: KANAYAMA, Horoshi, MINETA, Wataru, HOSOYA, Mutsumi
• Granted Patent: US 8,495,288 B2
• Time in Patent Office: Days
• US Class Current: 706/48
• CPC Class Codes: G06F 11/1453 using de-duplication of the data
• CPC Class Codes: G06F 11/1456 Hardware arrangements for backup
• CPC Class Codes: G06F 11/2071 using a plurality of controllers
• CPC Class Codes: G06F 11/2089 Redundant storage control functionality
• CPC Class Codes: G06F 12/0866 for peripheral storage systems, e.g. disk cache
• CPC Class Codes: G06F 2201/84 Using snapshots, i.e. a logical point-in-time copy of the data
• CPC Class Codes: G06F 3/0608 Saving storage space on storage systems
• CPC Class Codes: G06F 3/061 Improving I/O performance
• CPC Class Codes: G06F 3/0641 De-duplication techniques
• CPC Class Codes: G06F 3/0652 Erasing, e.g. deleting, data cleaning, moving of data to a wastebasket
• CPC Class Codes: G06F 3/0683 Plurality of storage devices

Abstract

A storage controller of the present invention narrows down the target for data comparison by comparing hash codes beforehand and rapidly detects duplicated data. A hash value setting unit sets a hash code in data received from a host. Hash code-attached data is stored in a logical volume. A microprocessor unit compares the hash codes for each comparison-targeted data. When hash codes match with one another, a data comparator compares the target data, and determines whether or not the data is duplicated data. When duplicated data is detected, the microprocessor unit removes the duplicated data.

Claims

1. A storage controller that comprises a first communications controller for carrying out data communications with a host computer, a second communications controller for carrying out data communications with a storage device, a cache memory that is used in the exchange of data between the first communications controller and the second communications controller, and a controller for controlling the first communications controller, the second communications controller and the cache memory respectively, the storage controller further comprising:

a determination data setting unit for setting, in respective data, determination data for making a primary determination as to whether or not the respective data matches with other data;

a duplicated data detector, which is for detecting whether or not a plurality of prescribed data is duplicated data, and which comprises a primary determination unit that makes a primary determination as to whether or not the respective prescribed data match with one another by comparing the respective determination data set in the respective prescribed data, and a secondary determination unit that compares the respective prescribed data and makes a secondary determination as to whether or not the respective prescribed data is duplicated data when the primary determination unit makes a primary determination that the respective prescribed data match with one another; and

a duplicated data processor that implements a preconfigured prescribed process for the duplicated data, when a secondary determination is that the respective prescribed data is duplicated data,

wherein at least the determination data setting unit and the secondary determination unit are configured as dedicated circuits that are separate from the controller.

2. The storage controller according to claim 1, wherein the duplicated data detector executes the primary determination by comparing the respective determination data set in the respective prescribed data when the respective prescribed data is transferred to the cache memory, and makes the secondary determination as to whether or not the respective prescribed data is the duplicated data by respectively reading out from the cache memory and comparing the respective prescribed data when the primary determination is that the respective prescribed data match with one another.

3. The storage controller according to claim 1 or claim 2, wherein the duplicated data processor stores only one data of the duplicated data, and deletes the other data of the duplicated data.

4. The storage controller according to claim 1 or claim 2, wherein the duplicated data processor stores only one data of the duplicated data, and sets link information to the one data in the other data of the duplicated data.

5. The storage controller according to claim 1 or claim 2, wherein the duplicated data processor transfers any newer data of the respective prescribed data to a prescribed storage area when the respective prescribed data is not the duplicated data.

6. The storage controller according to any of claims 1 through 5, wherein the determination data setting unit is provided in either one or both of the first communications controller and the second communications controller,

the primary determination unit is provided in the controller, and

the secondary determination unit is provided in any one or a plurality of the first communications controller, the second communications controller, the cache memory, and the controller.

7. The storage controller according to any of claims 1 through 6, wherein the setting of the determination data by the determination data setting unit, the detection of the duplicated data by the duplicated data detector, and the execution of the prescribed processing by the duplicated data processor are respectively executed in the each storage device.

8. The storage controller according to any of claims 1 through 7, wherein the respective prescribed data is any of a plurality of data received from the host computer or a plurality of data read out from the storage device, or data received from the host computer and data read out from the storage device.

9. A method for detecting duplicated data by using a storage controller that controls data communications between a host computer and a storage device, comprising the steps of:

using a dedicated circuit to set, in respective data, determination data for making a primary determination as to whether or not the respective data matches other data;

transferring to and storing in cache memory a plurality of prescribed data targeted for comparison;

making a primary determination by comparing whether or not respective determination data created for the respective prescribed data match with one another;

making a secondary determination as to whether or not the respective prescribed data is duplicated data by inputting the respective prescribed data into a comparison circuit and making a comparison thereof when the primary determination is that the determination data match with one another; and

implementing a preconfigured prescribed process for either any one or all of the respective prescribed data when the secondary determination is that the respective prescribed data is the duplicated data.