Establishing a synchronous replication relationship between two or more storage systems

Patent metadata

Field	Value
Publication number	US-11442825-B2
Application number	US-202117240334-A
Country	US
Kind code	B2
Filing date	Apr 26, 2021
Priority date	Mar 10, 2017
Publication date	Sep 13, 2022
Grant date	Sep 13, 2022

Abstract

Establishing a synchronous replication relationship between two or more storage systems, including: identifying, for a dataset, a plurality of storage systems across which the dataset will be synchronously replicated; configuring one or more data communications links between each of the plurality of storage systems to be used for synchronously replicating the dataset; exchanging, between the plurality of storage systems, timing information for at least one of the plurality of storage systems; and establishing, in dependence upon the timing information for at least one of the plurality of storage systems, a synchronous replication lease, the synchronous replication lease identifying a period of time during which the synchronous replication relationship is valid.

First claim

What is claimed is:

1. A method comprising:
exchanging, between a plurality of storage systems across which a dataset will be synchronously replicated, timing information for at least one of the plurality of storage systems; and
establishing, in dependence upon the timing information for at least one of the plurality of storage systems, a synchronous replication lease, the synchronous replication lease identifying a period of time during which the synchronous replication relationship is valid, wherein a request to modify the dataset may only be acknowledged after a copy of the dataset has been modified on each of the storage systems.

2. The method of claim 1 wherein the synchronous replication lease is calculated in dependence upon a value of a local clock that was received from another storage system.

3. The method of claim 1 further comprising wherein establishing the synchronous replication lease further comprises further comprises exchanging uncoordinated clocks between a plurality of storage systems.

4. The method of claim 1 further comprising
re-establishing a synchronous replication relationship after detecting that the synchronous replication lease has expired.

5. The method of claim 1 further comprising
attempting to take over I/O processing for the dataset after detecting that the synchronous replication lease has expired.

6. The method of claim 1 wherein at least one of the plurality of storage systems is a cloud-based storage system.

7. The method of claim 1 wherein the timing information for at least one of the plurality of storage systems includes a value which serves as a proxy for a clock value.

8. The method of claim 1 further comprising delaying the processing of I/O requests received after the synchronous replication lease has expired.

9. The method of claim 1 further comprising establishing a cluster membership lease.

10. An apparatus comprising a computer processor, a computer memory operatively coupled to the computer processor, the computer memory having disposed within it computer program instructions that, when executed by the computer processor, cause the apparatus to carry out the steps of:
exchanging, between a plurality of storage systems across which a dataset will be synchronously replicated, timing information for at least one of the plurality of storage systems; and
establishing, in dependence upon the timing information for at least one of the plurality of storage systems, a synchronous replication lease, the synchronous replication lease identifying a period of time during which the synchronous replication relationship is valid, wherein a request to modify the dataset may only be acknowledged after a copy of the dataset has been modified on each of the storage systems.

11. The apparatus of claim 10 wherein the synchronous replication lease is calculated in dependence upon a value of a local clock that was received from another storage system.

12. The apparatus of claim 10 wherein establishing the synchronous replication lease further comprises further comprises exchanging uncoordinated clocks between a plurality of storage systems.

13. The apparatus of claim 10 further comprising computer program instructions that, when executed by the computer processor, cause the apparatus to carry out
re-establishing a synchronous replication relationship after detecting that the synchronous replication lease has expired.

14. The apparatus of claim 10 further comprising computer program instructions that, when executed by the computer processor, cause the apparatus to carry out
attempting to take over I/O processing for the dataset after detecting that the synchronous replication lease has expired.

15. The apparatus of claim 10 wherein at least one of the plurality of storage systems is a cloud-based storage system.

16. A storage system comprising a computer processor and a computer memory operatively coupled to the computer processor, the computer memory having disposed within it computer program instructions that, when executed by the computer processor, cause the storage system to carry out the steps of:
sending, to a second storage system, timing information for the storage system;
receiving, from the second storage system, timing information for the second storage system; and
establishing a synchronous replication lease, the synchronous replication lease identifying a period of time during which the synchronous replication relationship is valid, wherein a request to modify the dataset may only be acknowledged after a copy of the dataset has been modified on each of the storage systems.

17. The storage system of claim 16 further comprising computer program instructions that, when executed by the computer processor, cause the storage system to carry out the step of setting, in dependence upon the timing information for the second storage system, a clock value in the storage system.

18. The storage system of claim 16 wherein the storage system is a cloud-based storage system.

19. The storage system of claim 16 wherein sending, to the second storage system, timing information for the storage system includes sending, to the second storage system, a most recently received value of a clock in the second storage system.

20. The storage system of claim 16 further comprising computer program instructions that, when executed by the computer processor, cause the storage system to carry
attempting to take over I/O processing for the dataset after detecting that the synchronous replication lease has expired.

Assignees

• Pure Storage Inc

Inventors

• Grunwald David
• Hodgson Steven
• Karr Ronald
• Trivedi Kunal
• Golden Christopher
• Gill Thomas
• Brooks Connor
• Shivani Zoheb

Classifications

• G06F3/0616 Primary

  in relation to life time, e.g. increasing Mean Time Between Failures [MTBF] · CPC title

• G06F3/0688

  Non-volatile semiconductor memory arrays · CPC title

• G06F12/1072

  Decentralised address translation, e.g. in distributed shared memory systems · CPC title

• G06F16/178

  Techniques for file synchronisation in file systems · CPC title

• G06F11/2064

  while ensuring consistency · CPC title