Implementing synchronization for remote disk mirroring

• US 9,898,210 B2
• Filed: 07/26/2016
• Issued: 02/20/2018
• Est. Priority Date: 12/15/2015
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Albertson, Aaron T., Miller, Robert, Nordland, Brian A., Thayib, Kiswanto
• Primary Examiner(s): Yi, David X
• Assistant Examiner(s): GOLDSCHMIDT, CRAIG S
• Application Number:
  US15/220,214
• Publication Number:
  US 20170168732A1
• Time in Patent Office: 574 Days
• Field of Search: None
• CPC Class Codes: G06F 12/1408 by using cryptography for digital transmission H04L9/00
• CPC Class Codes: G06F 2212/402 Encrypted data
• CPC Class Codes: G06F 3/0611 in relation to response time
• CPC Class Codes: G06F 3/0613 in relation to throughput
• CPC Class Codes: G06F 3/0619 in relation to data integrity, e.g. data losses, bit errors
• CPC Class Codes: G06F 3/065 Replication mechanisms
• CPC Class Codes: G06F 3/0653 Monitoring storage devices or systems
• CPC Class Codes: G06F 3/0658 Controller construction arrangements
• CPC Class Codes: G06F 3/067 Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS]
• CPC Class Codes: G06F 3/0689 Disk arrays, e.g. RAID, JBOD

Abstract

A method, and system for implementing enhanced fast full synchronization for remote disk mirroring in a computer system. A source backup copy is made locally available to a target for remote disk mirroring. Sectors are identified that are different between the source and target. A hash function is used over a block to be compared, with an adaptive number of tracking sectors per block, starting with a minimum block size.

Claims

1. A system for implementing enhanced fast full synchronization for remote disk mirroring in a computer system comprising:

a source storage and a target storage;

a tracking space bit map for remote disk mirroring used for full synchronization;

a respective memory controller coupled to said source storage and said target storage,

said respective memory controller providing a source backup copy locally available to the target for remote disk mirroring;

said respective memory controller identifying sectors that are different between the source and target during the full synchronization using a hash function over a block to be compared with no tracking sectors being sent, setting a tracking space bit in said tracking space bit map for each tracking sector to be sent to the target and setting a tracking space bit responsive to a corresponding tracking sector being changed on the source during the full synchronization includes said memory controller using the block being made up of an adaptive number of tracking sectors;

said respective memory controller using the adaptive number of tracking sectors per block, starting with a minimum block size; and

said respective memory controller responsive to the hashes matching between source and target, increasing a next block size by an integral number of tracking sectors.

2. The system as recited in claim 1 includes control code stored on a computer readable medium, and wherein said respective memory controller uses said control code for implementing full synchronization for remote disk mirroring.

3. The system as recited in claim 1 includes said respective memory controller on the source using said tracking space bit map for remote disk mirroring for the full synchronization.

4. The system as recited in claim 1 includes said respective memory controller turning off all the tracking space bits on the source indicating all tracking sectors are synchronized.

5. The system as recited in claim 1 includes said respective memory controller responsive to all hashes having been compared, sending the changed tracking sectors using said tracking space bit map.

6. The system as recited in claim 5 includes said memory controller on the source initially turning off all the tracking space bits on the source indicating all tracking sectors are synchronized.

7. The system as recited in claim 6 wherein said respective memory controller setting a tracking space bit in said tracking space bit map includes said memory controller setting said tracking space bit to 1.

8. The system as recited in claim 1 includes said respective memory controller responsive to the hashes not matching between source and target, decreasing a next block size by an integral number of tracking sectors.

11. The method as recited in claim 1 includes initially turning off all the tracking space bits on the source indicating all tracking sectors are synchronized.

12. The method as recited in claim 11 wherein setting a tracking space bit in said tracking space bit map includes setting the tracking space bit to 1.

13. The method as recited in claim 11 wherein initially turning off all the tracking space bits includes setting the tracking space bits to 0.

9. A method for implementing enhanced fast full synchronization for remote disk mirroring in a computer system comprising:

providing a source backup copy locally available to a target for remote disk mirroring;

providing a tracking space bit map for remote disk mirroring used for full synchronization;

identifying sectors that are different between the source and target using a hash function over a block to be compared during the full synchronization with no tracking sectors being sent,

setting a tracking space bit in said tracking space bit map for each tracking sector to be sent to the target;

setting a tracking space bit responsive to a corresponding tracking sector being changed on the source during the full synchronizations;

using the block being made up of an adaptive number of tracking sectors, starting at a minimum number of tracking sectors; and

responsive to the hashes matching between source and target, increasing a next block size by an integral number of tracking sectors.

10. The method as recited in claim 9 wherein said hash function includes a selected one of cryptographic hash algorithm including SHA-1 (Secure Hash Algorithm 1) and SHA-2 (Secure Hash Algorithm 2).

14. The method as recited in claim 9 includes responsive to all hashes having been compared, sending the changed tracking sectors using said tracking space bit map.

15. The method as recited in claim 9 responsive to the hashes not matching between source and target, decreasing a next block size by an integral number of tracking sectors.