Asynchronous replication of data

• US 20070055712A1
• Filed: 09/08/2005
• Published: 03/08/2007
• Est. Priority Date: 09/08/2005
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Boyd, Kenneth, Day, Kenneth, Wolfgang, John
• Granted Patent: US 7,519,633 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 16/273 Asynchronous replication or reconciliation
• CPC Class Codes: G06F 9/466 Transaction processing
• CPC Class Codes: Y10S 707/99952 Coherency, e.g. same view to multiple users
• CPC Class Codes: Y10S 707/99955 Archiving or backup

Abstract

In a data processing environment, data is replicated to a remote or secondary storage device in a manner which reduces the adverse performance effects and inefficient bandwidth usage imposed by the conventional one-transaction-at-a-time process. Transactions to be transferred are grouped by a replication manager by selecting transactions having start times earlier than the completion time of a first transaction. Thus, no transaction in a group will be dependent upon any other transaction in the group. Once selected, all transactions in the group may then be transferred to the secondary storage device.

Claims

1. A method for asynchronously copying data to a secondary data storage site, comprising:

receiving a plurality of data transactions from one or more host devices;

logging the times at which receipt of each transaction was started and completed;

identifying a first transaction having the earliest start time of all received transactions;

creating a first group comprising the first transaction and all other transactions having a start time which is earlier than the completion time of the first transaction; and

asynchronously transferring the transactions in the first group to a storage device.

2. The method of claim 1, further comprising, before transferring the transactions in the first group, removing from the first group any transaction having a start time which is later than the completion time of the transaction having the earliest completion time of all transactions in the first group.

3. The method of claim 1, further comprising:

receiving an acknowledgement that the transactions in the first group were successfully received by the storage device;

selecting a second transaction, the second transaction having the earliest start time of all remaining received transactions;

creating a second group comprising the second transaction and all other remaining transactions having a start time which is earlier than the completion time of the second transaction; and

asynchronously transferring the transactions in the second group to the storage device.

4. The method of claim 1, further comprising:

receiving an acknowledgement that a transaction of the first group was successfully received by the storage device;

identifying a second transaction having the earliest start time of all remaining transactions having a start time which is earlier than the earliest completion time of the transactions in the first group not yet acknowledged as being successfully received by the storage device;

creating a second group comprising the second transaction and all other transactions having a start time which is earlier than the earliest completion time of the transactions in the first group not yet acknowledged as being successfully received by the storage device; and

asynchronously transferring the transactions in the second group to the storage device.

5. The method of claim 1, further comprising:

before transferring the transactions in the first group, removing from the first group any transaction having a start time which is later than the completion time of the transaction having the earliest completion time of all transactions in the first group;

receiving an acknowledgement that a transaction of the first group was successfully received by the storage device;

identifying a second transaction having the earliest start time of all remaining transactions received from the one or more host devices having a start time which is earlier than the earliest completion time of the transactions in the first group not yet acknowledged as being successfully received by the storage device;

creating a second group comprising the second transaction and all other transactions having a start time which is earlier than the earliest completion time of the transactions in the first group not yet acknowledged as being successfully received by the storage device; and

asynchronously transferring the transactions in the second group to the storage device.

6. The method of claim 1, wherein:

the logging, identifying, creating and transferring are performed by a local replication manager; and

the storage device is a remote storage device.

7. The method of claim 1, wherein:

the logging is performed by a local replication manager;

the identifying, creating and transferring are performed by a remote replication manager; and

the storage device is a remote storage device.

8. A data replication manager, comprising:

a first interface through which data transactions are received from one or more host devices;

a second interface through which the data transactions are transferred to a primary storage device;

a third interface through which the data transactions are transferred to a secondary storage device;

a memory for storing a time at which receipt of each transaction was started and a time at which receipt of each transaction was completed; and

a processor operable to execute instructions for;

directing the transmission of the transactions through the second interface for storage in the primary storage device;

identifying a first transaction having the earliest start time of all received transactions;

creating a first group comprising the first transaction and all other transactions having a start time which is earlier than the completion time of the first transaction; and

directing the asynchronous transmission of the transactions in the first group through the third interface for storage on the secondary storage device.

9. The replication manager of claim 8, the processor further operable to execute instructions for, before transferring the transactions in the first group, removing from the first group any transaction having a start time which is later than the completion time of the transaction having the earliest completion time of all transactions in the first group.

10. The replication manager of claim 8, the processor further operable to execute instructions for:

receiving an acknowledgement that the transactions in the first group were successfully received by the secondary storage device;

selecting a second transaction, the second transaction having the earliest start time of all remaining received transactions;

creating a second group comprising the second transaction and all other remaining transactions having a start time which is earlier than the completion time of the second transaction; and

asynchronously transferring the transactions in the second group to the secondary storage device.

11. The replication manager of claim 8, the processor further operable to execute instructions for:

receiving an acknowledgement that a transaction of the first group was successfully received by the storage device;

identifying a second transaction having the earliest start time of all remaining transactions having a start time which is earlier than the earliest completion time of the transactions in the first group not yet acknowledged as being successfully received by the storage device;

creating a second group comprising the second transaction and all other transactions having a start time which is earlier than the earliest completion time of the transactions in the first group not yet acknowledged as being successfully received by the storage device; and

asynchronously transferring the transactions in the second group to the secondary storage device.

12. A computer program product of a computer readable medium usable with a programmable computer, the computer program product having computer-readable code embodied therein for copying data to a secondary data storage site, the computer-readable code comprising instructions for:

receiving a plurality of data transactions from one or more host devices;

logging the times at which receipt of each transaction was started and completed;

identifying a first transaction having the earliest start time of all received transactions;

creating a first group comprising the first transaction and all other transactions having a start time which is earlier than the completion time of the first transaction; and

asynchronously transferring the transactions in the first group to a storage device.

13. The computer program product of claim 12, the computer-readable code further comprising instructions for, before transferring the transactions in the first group, removing from the first group any transaction having a start time which is later than the completion time of the transaction having the earliest completion time of all transactions in the first group.

14. The computer program product of claim 12, the computer-readable code further comprising instructions for:

receiving an acknowledgement that the transactions in the first group were successfully received by the storage device;

selecting a second transaction, the second transaction having the earliest start time of all remaining received transactions;

creating a second group comprising the second transaction and all other transactions having a start time which is earlier than the completion time of the second transaction; and

asynchronously transferring the transactions in the second group to the storage device.

15. The computer program product of claim 12, the computer-readable code further comprising instructions for:

receiving an acknowledgement that a transaction of the first group was successfully received by the storage device;

identifying a second transaction having the earliest start time of all remaining transactions having a start time which is earlier than the earliest completion time of the transactions in the first group not yet acknowledged as being successfully received by the storage device;

creating a second group comprising the second transaction and all other remaining transactions having a start time which is earlier than the earliest completion time of the transactions in the first group not yet acknowledged as being successfully received by the storage device; and

asynchronously transferring the transactions in the second group to the storage device.

16. The computer program product of claim 12, the computer-readable code further comprising instructions for:

before transferring the transactions in the first group, removing from the first group any transaction having a start time which is later than the completion time of the transaction having the earliest completion time of all transactions in the first group;

receiving an acknowledgement that a transaction of the first group was successfully received by the storage device;

identifying a second transaction having the earliest start time of all remaining transactions received from the one or more host devices;

creating a second group comprising the second transaction and all other transactions having a start time which is earlier than the completion time of the second transaction;

removing from the second group any transaction having a start time which is later than the completion time of the transaction having the earliest completion time of all transactions in the second group; and

asynchronously transferring the transactions in the second group to the storage device.

17. A method for copying data to a secondary data storage site, comprising:

receiving a plurality of data transactions from one or more host devices;

creating a first group of transactions in which no transaction is dependent upon any other transaction in the first group; and

asynchronously transferring the transactions in the first group to a storage device.

18. The method of claim 17, further comprising:

receiving an acknowledgement that the transactions in the first group were successfully received by the storage device;

creating a second group of transactions in which no transaction is dependent upon any other transaction in the second group; and

asynchronously transferring the transactions in the second group to the storage device.

19. The method of claim 17, wherein:

creating and transferring are performed by a local replication manager; and

the storage device is a remote storage device.

20. The method of claim 17, wherein:

the creating and transferring are performed by a remote replication manager; and

the storage device is a remote storage device.