Data access responding system, storage system, client apparatus, cache apparatus, and method for accessing data access responding system

• US 20060041614A1
• Filed: 04/26/2005
• Published: 02/23/2006
• Est. Priority Date: 05/21/2003
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Oe, Kazuichi
• Granted Patent: US 7,366,835 B2
• Time in Patent Office: Days
• US Class Current: 709/203
• CPC Class Codes: G06F 12/0868 Data transfer between cache memory and other subsystems, e.g. storage devices or host systems
• CPC Class Codes: G06F 2212/263 Network storage, e.g. SAN or NAS
• CPC Class Codes: G06F 2212/314 In storage network, e.g. network attached cache
• CPC Class Codes: G06F 2212/463 File
• CPC Class Codes: G06F 3/0611 in relation to response time
• CPC Class Codes: G06F 3/0659 Command handling arrangements, e.g. command buffers, queues, command scheduling
• CPC Class Codes: G06F 3/0683 Plurality of storage devices

Abstract

A control apparatus provides a transfer instruction to one of storage apparatus and a cache apparatus, in which relevant data is stored, when receiving an access request from a client apparatus for the data for which the storage location is managed; and the one of the storage apparatus and the cache apparatus receiving the transfer instruction directly returns a reply message, to the client apparatus, having information of the storage location of the data added thereto, which data the access request requests.

Claims

1. A data access responding system comprising a storage apparatus storing data;

a cache apparatus which acts as a cache for the data stored in said storage apparatus;

a client apparatus processing the data, and a control apparatus managing storage locations of the data in said storage apparatus and in said cache apparatus, which are connected via a communication network, wherein;

said control apparatus provides a transfer instruction to one of said storage apparatus and said cache apparatus, in which one the relevant data is stored, when receiving an access request from said client apparatus for the data; and

said one of said storage apparatus and said cache apparatus receiving said transfer instruction directly returns to said client apparatus a reply message accompanied by information of the storage location of the relevant data.

2. The data access responding system as claimed in claim 1, wherein:

said one of said storage apparatus and said cache apparatus in which the relevant data is stored comprises said cache apparatus; and

said client apparatus has a memory storing said information of the storage location.

3. The data access responding system as claimed in claim 2, wherein:

said client apparatus directly accesses said cache apparatus when making an access request for the data for which the information of the storage location is stored in said memory, without making an access request to said control apparatus, and has the data transferred thereto from said cache apparatus.

4. The data access responding system as claimed in claim 3, wherein:

said client apparatus is prevented from directly accessing said cache apparatus for the data, as a result of the information of the storage location of the data being changed.

5. The data access responding system as claimed in claim 4, wherein:

said client apparatus deletes the information of the storage location from said memory and makes access request to said control apparatus, when direct access to said cache apparatus is not allowed.

6. The data access responding system as clamed in claim 3, wherein:

said client apparatus transmits to said control apparatus a data consistency instruction for the data written in said cache apparatus, after accessing said cache apparatus and writing the data therein when including in the access request a data writing instruction.

7. The data access responding system as claimed in claim 6, wherein:

said cache apparatus responds to an instruction received from said control apparatus which has received the data consistency instruction, and copies the data once written in said cache apparatus then to said storage apparatus.

8. A data access responding system comprising a storage apparatus storing data;

a cache apparatus which acts as a cache for the data stored in said storage apparatus;

a client apparatus processing the data, and a control apparatus managing storage locations of the data in said storage apparatus and in said cache apparatus, which communicate each other via a communication network, wherein;

said client apparatus has a memory having a cache area, and notifying said control apparatus of information concerning said cache area.

9. The data access responding system as claimed in claim 8, wherein:

said control apparatus stores, in said cache area, information of the storage location of the data, for which data an access frequency to said cache apparatus is high.

10. The data access responding system as claimed in claim 9, wherein:

said control apparatus arbitrarily deletes the information of the storage location from said cache area.

11. The data access responding system as claimed in claim 8, wherein:

said client apparatus carries out self management of the data for which the access frequency is high, requests said control apparatus for the information concerning the storage location of the data having a predetermined access frequency, and stores the information of the storage location in said cache area.

12. The data access responding system as claimed in claim 11, wherein:

said client apparatus arbitrarily deletes the information of the storage location from said cache area.

13. The data access responding system as claimed in claim 9, wherein:

said client apparatus searches for the information of the storage location from said cache area for making an access request for the data for which the storage location is managed by said control apparatus, and, when determining the relevant exists in said cache apparatus from the information stored in said cache area, said client apparatus directly access said cache apparatus without making an access request to said control apparatus, and has the data transferred thereto from said cache apparatus.

14. The data access responding system as claimed in claim 11, wherein:

said client apparatus searches for the information of the storage location from said cache area for making an access request for the data for which the storage location is managed by said control apparatus, and, when determining the relevant exists in said cache apparatus from the information stored in said cache area, said client apparatus directly access said cache apparatus without making an access request to said control apparatus, and has the data transferred thereto from said cache apparatus.

15. The data access responding system as claimed in claim 9, wherein:

said client apparatus transmits to said control apparatus a data consistency instruction for the data written in said cache apparatus after accessing said cache apparatus and writing the data therein by including in the access request a data writing instruction.

16. The data access responding system as claimed in claim 11, wherein:

said client apparatus transmits to said control apparatus a data consistency instruction for the data written in said cache apparatus after accessing said cache apparatus and writing the data therein by including in the access request a data writing instruction.

17. The data access responding system as claimed in claim 15, wherein:

said cache apparatus responds to an instruction received from said control apparatus which has received the data consistency instruction, and copies the data once written in said cache apparatus then to said storage apparatus.

18. The data access responding system as claimed in claim 16, wherein:

said cache apparatus responds to an instruction received from said control apparatus which has received the data consistency instruction, and copies the data once written in said cache apparatus then to said storage apparatus.

19. A storage system comprising a storage apparatus storing data;

a cache apparatus which acts as a cache for the data stored in said storage apparatus; and

a control apparatus managing storage locations of the data in said storage apparatus and in said cache apparatus, which are connected via a communication network, wherein;

said control apparatus responds an access request received from a client apparatus for the data for which said control apparatus manages the storage location, and provides one of said storage apparatus and said cache apparatus, in which one the relevant data is stored, with a data transfer instruction for the data; and

said one of said storage apparatus and said cache apparatus receiving said data transfer instruction returns a reply message to said client apparatus, to which message information concerning the storage location of the data is attached.

20. A client apparatus connected to a storage system comprising a storage apparatus storing data;

a cache apparatus which acts as a cache for the data stored in said storage apparatus; and

a control apparatus managing storage locations of the data in said storage apparatus and in said cache apparatus, which are connected via a communication network, wherein;

said client apparatus makes access request to said control apparatus, receives a reply message from one of said storage apparatus and said cache apparatus, in which one the relevant is stored, said message including information concerning the storage location of the data, and obtains the data by directly accessing said one of said storage apparatus and said cache apparatus.

21. A cache apparatus which acts as a cache for data stored in a storage apparatus, wherein:

said cache apparatus is connected to, via a communication network, said storage apparatus, a client apparatus and a control apparatus managing storage locations of data in said storage apparatus and in said cache apparatus, responds to a data transfer instruction received from said control apparatus originating from an access request received from said client apparatus, and returns a reply message to said client apparatus, to which message information concerning the storage location of the relevant data is attached.

22. A method of accessing a data access responding system which comprises a storage apparatus storing data;

a cache apparatus which acts as a cache for the data stored in said storage apparatus;

a client apparatus processing the data, and a control apparatus managing storage locations of the data in said storage apparatus and in said cache apparatus, which are connected via a communication network, said method comprising the steps of;

a) said control apparatus providing a transfer instruction to one of said storage apparatus and said cache apparatus, in which one the relevant data is stored, when receiving an access request from said client apparatus for the data for which said control apparatus manages the storage location; and

b) said one of said storage apparatus and said cache apparatus, which receives the transfer instruction, directly returning a reply message, to said client apparatus, having information of the storage location of the relevant data attached thereto.

23. The method of accessing the data access responding system as claimed in claim 22, wherein:

said client apparatus stores the information of the storage location in a cache memory, and directly accesses said one of said storage apparatus and said cache apparatus in which desired data is stored without making an access request to said control apparatus when making an access request for the data for which the information of the storage location is stored in said cache memory.

24. The method of accessing the data access responding system as claimed in claim 22, wherein:

said client apparatus has a memory having a cache area; and

said method further comprises the steps of;

c) said client apparatus notifying said control apparatus of information concerning said cache area; and

d) the information of the storage location of the data for which an access frequency to said cache apparatus is high being stored in said cache area.

25. The method of accessing the data access responding system as claimed in claim 22, further comprising the step of:

c) said client apparatus searching for the information of the storage location from said cache area when making an access request for the data for which the storage location is managed by said control apparatus, and, when determining from the information stored in said cache area that the relevant data exists in said cache apparatus, said client apparatus directly accessing said cache apparatus without making an access request to said control apparatus.