Distributed storage of data in a cloud storage system

• US 9,052,962 B2
• Filed: 03/30/2012
• Issued: 06/09/2015
• Est. Priority Date: 03/31/2011
• Status: Active Grant

• Current Assignee: KT Corporation
• Original Assignee: KT Corporation
• Inventors: Lee, Eo-Hyung, Kim, Mi-Jeom, Kim, Hyo-Min, Park, Chang-Sik, Hwang, Jin-Kyung
• Primary Examiner(s): Nguyen, Loan T
• Application Number:
  US13/435,064
• Publication Number:
  US 20120259901A1
• Time in Patent Office: 1,166 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: G06F 16/27 Replication, distribution or synchronisation of data between databases or within a distributed database system; Distributed database system architectures therefor
• CPC Class Codes: G06F 9/5072 Grid computing

Abstract

Provided are apparatus and method for distributedly storing an object in a plurality of data centers included in a cloud storage system. In the method, an object may be divided into a plurality of sub-objects each having a fragmentation size. Then, the sub-objects may be distributedly stored in at least one data center based on weights of the plurality of data centers.

Claims

1. A method for distributedly storing data in a plurality of data centers in a cloud storage system, the method comprising:

receiving a storing request from a client;

dividing an object associated with the storing request into a plurality of sub-objects each having a fragmentation size, wherein the fragmentation size is determined by dividing an average object size by a sum of weights of the data centers, the average object size corresponding to an average size of objects stored in the cloud storage system and periodically calculated and updated;

assigning a correlation value to each one of the plurality of sub-objects;

creating a file name of each one of the plurality of sub-objects;

calculating a first hash value, as the correlation value, of each one of the plurality of sub-objects;

calculating a second hash value, as a representative value, of each one of the plurality of sub-objects;

deciding data centers among the plurality of data centers to store the plurality of sub-objects based on the representative value of each one of the plurality of sub-objects, wherein the decided data centers are selected from the plurality of data centers based on the second hash value of each one of the plurality of sub-objects;

determining a number of sub-objects to be stored in each one of the decided data centers based on a weight of each data center; and

distributedly storing the plurality of sub-objects in the decided data centers based on the determined number of sub-objects, wherein for the distributedly storing a corresponding weight of a data center is based on a ratio of a storage capacity of the data center to storage capacities of other data centers.

2. The method of claim 1, comprising determining the weight based on storage resources of each of the plurality of data centers.

3. The method of claim 2, wherein the storage resources include storage capacities of the plurality of data centers.

4. The method of claim 1, wherein for the distributedly storing the sub-objects, more sub-objects are stored in the data center having a higher weight than the data center having a lower weight.

5. The method of claim 1, comprising storing and managing the weights of the data center in a form of metadata.

6. The method of claim 1, comprising receiving the object from the client with the storing request in the cloud storage system.

7. The method of claim 1, further comprising:

calculating the first hash value of the object; and

assigning the first hash value to the sub-objects as the correlation value.

8. The method of claim 7, comprising storing and managing the first hash value of the object and the correlation value of the sub-objects as metadata.

9. The method of claim 7, comprising determining, with the first hash value of the object and the correlation value of the sub-objects, whether the object is related to the sub-objects and whether the sub-objects are related to each other.

10. The method of claim 1, wherein the deciding data centers among the plurality of data centers includes:

calculating the second hash value, as the representative value, of each sub-object based on the filename of each sub-objects; and

determining at least one data center to store sub-objects based on the second hash value of a corresponding sub-object.

11. The method of claim 10, comprising:

processing the second hash value of each sub-object into a reference number and indicating, based on the second hash value, at least one data center in metadata stored in a metadata database.

12. An apparatus for distributedly storing an object in a plurality of data centers included in a cloud storage system, the apparatus comprising:

a memory;

a divider configured to receive a storing request from a client and divide an object associated with the storing request into a plurality of sub-objects each having a fragmentation size, wherein, the fragmentation size is determined based on a result of dividing an average object size by a sum of the weights of the data centers, the average object size corresponding to an average size of objects stored in the cloud storage system and periodically calculated and updated;

a storage location decider configured to decide data centers among the plurality of data centers to store the plurality of sub-objects based on a representative value of each one of the plurality of sub-objects, wherein the storage location decider is configured to assign a correlation value to each one of the plurality of sub-objects, to create a file name of each one of the plurality of sub-objects, to calculate a first hash value, as the correlation value, of each one of the plurality of sub-objects, and to calculate a second hash value, as the representative value, of each one of the plurality of sub-objects, wherein the decided data centers are selected from the plurality of data centers based on the second hash value of each one of the plurality of sub-objects;

a distributor configured to determining a number of sub-objects to be stored in each one of the decided data centers based on a weight of each data center and distributedly store the plurality of sub-objects in the decided data centers based on the determined number of sub-objects; and

a weight of a data center is a ratio of a storage capacity of the data center to storage capacities of other data centers.

13. The apparatus of claim 12, further comprising:

a correlation unit configured to calculate the first hash value of the object and assign the first hash value to the sub-objects as the correlation value;

a naming unit configured to create a file name of each one of the plurality of sub-objects; and

the storage location decider configured to calculate the second hash value, as the representative value, of each sub-object based on the filename of each sub-object and to determine at least one data center to store the sub-objects based on the second hash value of each sub-object.

14. The apparatus of claim 13, wherein:

the storage location decider is configured to i) obtain reference numbers that indicate the at least one data center in metadata stored in a metadata database by processing the second hash value of each sub-object and ii) determine data centers to store the sub-objects based on the reference numbers; and

the distributor is configured to store more sub-objects in the data center having a higher weight than the data center having a lower weight.