DISTRIBUTED DATA STORAGE SYSTEM, DATA DISTRIBUTION METHOD, AND APPARATUS AND PROGRAM TO BE USED FOR THE SAME

• US 20080201336A1
• Filed: 02/19/2008
• Published: 08/21/2008
• Est. Priority Date: 02/20/2007
• Status: Active Grant

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: YAMATO, JUNICHI
• Granted Patent: US 8,239,621 B2
• Time in Patent Office: Days
• US Class Current: 707/10
• CPC Class Codes: G06F 16/10 File systems; File servers

Abstract

There is provided a distributed data storage system for splitting content-data into a plurality of split data and storing a plurality of copy data corresponding to at least one of the plurality of split data in a plurality of memory devices. The system comprises a copying management information storing unit and a access location determining unit. The copying management information storing unit stores copying management information indicating a storage location of the copy data corresponding to the split data. The access location determining unit determines at least one of the plurality of memory devices storing the copy data corresponding to the split data as an access location for accessing split data.

Claims

1. A distributed data storage system for splitting content-data into a plurality of split data and storing a plurality of copy data corresponding to at least one of the plurality of split data in a plurality of memory devices, the system comprising:

copying management information storing means for storing copying management information indicating a storage location of the copy data corresponding to the split data; and

access location determining means for determining at least one of the plurality of memory devices storing the copy data corresponding to the split data as an access location for accessing split data.

2. The distributed data storage system according to claim 1, wherein:

the access location determining means determines, for a host terminal reading at least part of content-data, at least one of the plurality of memory devices storing the copy data corresponding to the split data forming the at least part of content-data as an access location for accessing split data, and notifies it of the host terminal.

3. The distributed data storage system according to claim 1, wherein:

the access location determining means determines, at a host terminal reading at least part of content-data, at least one of the plurality of memory devices storing the copy data corresponding to the split data forming the at least part of content-data as an access location for accessing split data.

4. The distributed data storage system according to claim 1, wherein:

the access location determining means randomly determines at least one of the plurality of memory devices storing the plurality of copy data corresponding to the split data based on a random number.

5. The distributed data storage system according to claim 1, wherein:

the access location determining means determines a memory device having the lowest load in a plurality of memory devices storing a plurality of copy data corresponding to at least one of the plurality of split data as an access location.

6. The distributed data storage system according to claim 1, further comprising:

split data management means for dividing content-data into a plurality of split data and determining a plurality of memory devices as storage locations of a plurality of copy data corresponding at least one of the plurality of split data, wherein;

the copying management information strong means stores copying management information indicating the storage locations of the plurality of copy data determined by the split data management means.

7. The distributed data storage system according to claim 6, wherein:

the split data management means determines storage locations of copy data so as to make memory devices uniformly store the plurality of copy data corresponding to the split data.

8. The distributed data storage system according to claim 6, wherein:

the split data management means determines assignment locations of copy data so as to make memory devices store a plurality of copy data corresponding to a predetermined number of split data that are continuous in content-data in a distributed manner.

9. The distributed data storage system according to claim 6, wherein:

the split data management means determines assignment locations of copy data so as to uniformize the share numbers of combinations of memory devices, the share number being the number of copy data corresponding to same split data shared by two memory devices.

10. The distributed data storage system according to claim 9, wherein:

when determining an assignment location of copy data while the assignment location of copy data corresponding to the same split data is already determined, the split data management means determines the memory device showing the smallest share number when combined with the memory device already determined as assignment location of the copy data out of the memory devices except the memory device already determined as assignment location.

11. The distributed data storage system according to claim 6, wherein:

when a memory device is disabled, the split data management means deletes information indicating a disabled memory device as storage location from the copying management information storage means.

12. The distributed data storage system according to claim 6, further comprising:

copying process means for executing a copying process of copying data from a memory device to a memory device and a deletion process of deleting copy data from a memory device according to an instruction from the split data management means, wherein;

the split data management means

determines a new assignment location for the copy data assigned to a disabled memory device as assignment location,

determines a memory device as copy originating memory device out of the memory devices storing copy data corresponding to the split data same as the former copy data, and

causes the copying process means to execute the copying process of copying the copy data from the originating memory device.

13. The distributed data storage system according to claim 6, further comprising:

copying process means for executing a copying process of copying data from a memory device to a memory device and a deletion process of deleting copy data from a memory device according to an instruction from the split data management means, wherein;

the split data management means

determines a new assignment location for copy data at a predetermined timing according to the copying management information and

causes the copying process means to execute the copying process of copying data to the new assignment location and the deletion process of deleting copy data from the former assignment location.

14. The distributed data storage system according to claim 6, further comprising:

number of copies planning means for determining the number of copies that is the number of copy data to be stored in memory devices for split data forming content-data, wherein;

the split data management means determines the assignment locations of copy data corresponding to the split data according to the number of copies of the split data as determined by the number of copies planning means.

15. The distributed data storage system according to claim 14, wherein:

the number of copies planning means determines the number of copies of each split data according to the position of the split data in content-data.

16. The distributed data storage system according to claim 15, wherein:

when the split data including data at the leading position of content-data is given and content-data are provided with chapters, the number of copies planning means makes the number of copies of split data including data at the leading position of each chapter larger than the number of copies of any other split data of content-data.

17. The distributed data storage system according to claim 14, wherein:

the number of copies planning means determines the number of copies of split data according to the access requests of content-data.

18. The distributed data storage system according to claim 17, wherein:

the number of copies planning means determines the number of copies of split data according to the predicted access requests or the access requests of content-data, the processing capacity of each memory device and the safety coefficient defined by the system.

19. The distributed data storage system according to claim 14, further comprising:

copying process means for executing a copying process of copying data from a memory device to a memory device and a deletion process of deleting copy data from a memory device according to an instruction from the split data management means, wherein;

the split data management means

determines a new assignment location of copy data corresponding to split data or an assignment location for deleting copy data corresponding to the split data so as to make the number of copies of the split data as determined by the number of copies planning means and the number of copy data corresponding to the split data and stored in memory devices agree with each other and

causes the copying process means to execute the copying process of copying the copy data or deletion process of deleting the copy data.

20. A split data management apparatus used for a distributed data storage system for splitting content-data into a plurality of split data and storing a plurality of copy data corresponding to at least one of the plurality of split data in a plurality of memory devices, the apparatus being adapted to notify a host terminal reading at least part of content-data of the access location for accessing split data forming content-data, the apparatus comprising:

access location determining means for determining at least one memory device as an access location for accessing the split data out of the memory devices storing copy data corresponding to the split data according to the copying management information indicating the assignment locations of copy data corresponding to the split data included in content-data read range of the host terminal.

21. A host terminal used for a distributed data storage system for splitting content-data into a plurality of split data and storing a plurality of copy data corresponding to at least one of the plurality of split data in a plurality of memory devices, the host terminal being adapted to access the plurality of memory devices storing split data forming content-data in order to read at least part of content-data, the host terminal comprising:

access location determining means for determining at least one of the plurality of memory devices as an access location for accessing the split data out of the memory devices storing copy data corresponding to the split data according to the copying management information indicating the assignment locations of copy data corresponding to the split data included in content-data read range thereof.

22. A data distribution method for a distributed data storage system for splitting content-data into a plurality of split data and storing a plurality of copy data corresponding to at least one of the plurality of split data in a plurality of memory devices, the method comprising:

a step in which copying management information storing means stores copying management information indicating the storage locations of copy data corresponding to split data; and

a step in which access location determining means determines at least one of the plurality of memory devices storing the copy data corresponding to split data as location for accessing the split data according to the copying management information.

23. The data distribution method according to claim 22, further comprising:

a step of in which the access location determining means determines, for a host terminal reading at least part of content-data, at least one of the plurality of memory devices storing the copy data corresponding to the split data forming the at least part of content-data as an access location for accessing split data, and notifies it of the host terminal.

24. The data distribution method according to claim 22, further comprising:

a step in which the access location determining means determines, at a host terminal reading at least part of content-data, at least one of the plurality of memory devices storing the copy data corresponding to the split data forming the at least part of content-data as an access location for accessing split data.

25. The data distribution method according to claim 22, further comprising:

a step in which the access location determining means randomly determines at least one of the plurality of memory devices storing the plurality of copy data corresponding to the split data based on a random number.

26. The data distribution method according to claim 22, further comprising:

a step in which the access location determining means determines a memory device having the lowest load in a plurality of memory devices storing a plurality of copy data corresponding to at least one of the plurality of split data as an access location.

27. The distributed data storage method according to claim 22, further comprising:

a step in which split data management means divides content-data into a plurality of split data and determines a plurality of memory devices as storage locations of a plurality of copy data corresponding at least one of the plurality of split data; and

a step in which the copying management information strong means stores copying management information indicating the storage locations of the plurality of copy data determined by the split data management means.

28. The data distribution method according to claim 27, further comprising:

a step in which the split data management means determines storage locations of copy data so as to make memory devices uniformly store the plurality of copy data corresponding to the split data.

29. The data distribution method according to claim 27, further comprising:

a step in which the split data management means determines assignment locations of copy data so as to make memory devices store a plurality of copy data corresponding to a predetermined number of split data that are continuous in content-data in a distributed manner.

30. The data distribution method according to claim 27, further comprising:

a step in which the split data management means determines assignment locations of copy data so as to uniformize the share numbers of combinations of memory devices, the share number being the number of copy data corresponding to same split data shared by two memory devices.

31. The data distribution method according to claim 30, further comprising:

a step in which, when determining an assignment location of copy data while the assignment location of copy data corresponding to the same split data is already determined, the split data management means determines the memory device showing the smallest share number when combined with the memory device already determined as assignment location of the copy data out of the memory devices except the memory device already determined as assignment location.

32. The data distribution method according to claim 27, further comprising:

a step in which, when a memory device is disabled, the split data management means deletes information indicating a disabled memory device as storage location from the copying management information storage means.

33. The data distribution method according to claim 27, further comprising:

a step in which copying process means executes a copying process of copying data from a memory device to a memory device and a deletion process of deleting copy data from a memory device according to an instruction from the split data management means; and

a step in which the split data management means

determines a new assignment location for the copy data assigned to a disabled memory device as assignment location,

determines a memory device as copy originating memory device out of the memory devices storing copy data corresponding to the split data same as the former copy data, and

causes the copying process means to execute the copying process of copying the copy data from the originating memory device.

34. The data distribution method according to claim 27, further comprising:

a step in which copying process means executes a copying process of copying data from a memory device to a memory device and a deletion process of deleting copy data from a memory device according to an instruction from the split data management means; and

a step in which the split data management means

determines a new assignment location for copy data at a predetermined timing according to the copying management information and

causes the copying process means to execute the copying process of copying data to the new assignment location and the deletion process of deleting copy data from the former assignment location.

35. The data distribution method according to claim 27, further comprising:

a step in which number of copies planning means determines the number of copies that is the number of copy data to be stored in memory devices for split data forming content-data; and

a step in which the split data management means determines the assignment locations of copy data corresponding to the split data according to the number of copies of the split data as determined by the number of copies planning means.

36. The data distribution method according to claim 35, further comprising:

a step in which the number of copies planning means determines the number of copies of each split data according to the position of the split data in content-data.

37. The data distribution method according to claim 36, further comprising:

a step in which, when the split data including data at the leading position of content-data is given and content-data are provided with chapters, the number of copies planning means makes the number of copies of split data including data at the leading position of each chapter larger than the number of copies of any other split data of content-data.

38. The data distribution method according to claim 35, further comprising:

a step in which the number of copies planning means determines the number of copies of split data according to the access requests of content-data.

39. The data distribution method according to claim 38, further comprising:

a step in which the number of copies planning means determines the number of copies of split data according to the predicted access requests or the access requests of content-data, the processing capacity of each memory device and the safety coefficient defined by the system.

40. The data distribution method according to claim 35, further comprising:

a step in which copying process means executes a copying process of copying data from a memory device to a memory device and a deletion process of deleting copy data from a memory device according to an instruction from the split data management means; and

a step in which the split data management means

determines a new assignment location of copy data corresponding to split data or an assignment location for deleting copy data corresponding to the split data so as to make the number of copies of the split data as determined by the number of copies planning means and the number of copy data corresponding to the split data and stored in memory devices agree with each other and

causes the copying process means to execute the copying process of copying the copy data or deletion process of deleting the copy data.

41. A computer program, encoded in a computer-readable medium, for a split data management apparatus in a distributed data storage system for splitting content-data into a plurality of split data and storing a plurality of copy data corresponding to at least split data in a plurality of memory devices, the apparatus notifying an access location for accessing split data of content-data to a host terminal reading at least part of content-data, the program causing a computer to execute a process of:

determining at least one of the plurality of memory devices storing the copy data corresponding to the split data as an access location for accessing split data according to the copying management information indicating the location of the copy data corresponding to the split data included in content-data reading range of the host terminal.

42. The computer program according to claim 41, further causing the computer to execute a process of:

dividing content-data into a plurality of split data and determining a plurality of memory devices as storage locations of a plurality of copy data corresponding at least one of the plurality of split data.

43. A computer program, encoded in a computer-readable medium, for a host terminal in a distributed data storage system for splitting content-data into a plurality of split data and storing a plurality of copy data corresponding to at least one of the plurality of split data in a plurality of memory devices, the host terminal being configured to access the plurality of memory devices storing split data forming content-data in order to read at least part of content-data, the program causing a computer to execute a process of:

determining at least one of the plurality of memory devices as an access location for accessing the split data out of the memory devices storing copy data corresponding to the split data according to copying management information indicating an assignment location of copy data corresponding to the split data included in content-data read range thereof.