CONCURRENT REMOTE IO PROCESSING FOR SYNCHRONOUS REPLICATION

• US 20200133807A1
• Filed: 10/24/2018
• Published: 04/30/2020
• Est. Priority Date: 10/24/2018
• Status: Active Grant

• Current Assignee: Emc IP Holding Company LLC (Dell Technologies Inc.)
• Original Assignee: Emc IP Holding Company LLC (Dell Technologies Inc.)
• Inventors: Tannous, Toufic, Bora, Bhaskar, Vokaliga, Deepak
• Granted Patent: US 10,936,451 B2
• Time in Patent Office: Days
• CPC Class Codes: G06F 11/2064 while ensuring consistency
• CPC Class Codes: G06F 11/2076 Synchronous techniques
• CPC Class Codes: G06F 11/2082 Data synchronisation
• CPC Class Codes: G06F 11/2094 Redundant storage or storage space G06F11/2056 takes precedence
• CPC Class Codes: G06F 12/0292 using tables or multilevel address translation means G06F12/023 takes precedence; address translation in virtual memory systems G06F12/10
• CPC Class Codes: G06F 12/084 with a shared cache
• CPC Class Codes: G06F 12/0868 Data transfer between cache memory and other subsystems, e.g. storage devices or host systems
• CPC Class Codes: G06F 12/126 with special data handling, e.g. priority of data or instructions, handling errors or pinning
• CPC Class Codes: G06F 2201/82 Solving problems relating to consistency ensuring consistency in mirrored systems G06F11/2064
• CPC Class Codes: G06F 2201/825 the problem or solution involving locking
• CPC Class Codes: G06F 3/061 Improving I/O performance
• CPC Class Codes: G06F 3/0611 in relation to response time
• CPC Class Codes: G06F 3/065 Replication mechanisms
• CPC Class Codes: G06F 3/0659 Command handling arrangements, e.g. command buffers, queues, command scheduling
• 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

In a data storage system in which a first storage array and a second storage array maintain first and second replicas of a production volume, the first storage array is responsive to a write command from a host to send a notification to the second storage array indicating that the replicated production volume will be updated. The notification has information that enables the second storage array to implement pre-processing steps to prepare for subsequent receipt of data associated with the write command. Both storage arrays implement the pre-processing steps at least partly concurrently. When the data associated with the write command is subsequently received, the first storage array writes the data to cache and then sends a copy of the data to the second storage array, i.e. in series. The second storage array then writes the data to cache. Elapsed time between receipt of the write command and returning an acknowledgment to the host may be improved by concurrent pre-processing.

Claims

1. An apparatus comprising:

a first storage array comprising a plurality of interconnected computing nodes, each of the computing nodes comprising at least one processor and non-transitory memory, and a plurality of groups of data storage drives, each group of data storage drives connected with one of the computing nodes, wherein the first storage array maintains a first replica of a replicated volume comprising contiguous logical block addresses that map to non-contiguous addresses of the data storage drives;

program code, responsive to receipt of an IO command that will update the replicated volume, which generates a notification an IO that will update the replicated volume is impending, the notification comprising information that enables implementation of pre-processing to prepare for receipt of data associated with the impending IO;

program code that provides the notification to a second storage array that maintains a second replica of the replicated volume; and

program code that implements the pre-processing to prepare for receipt of data associated with the impending IO at least partly concurrently with implementation of the pre-processing by the second storage array.

2. The apparatus of claim 1 wherein the notification indicates LBAs (logical block addresses) affected by the impending IO.

3. The apparatus of claim 1 wherein the notification indicates at least one of:

device number, cylinder number, head (track), and size.

4. The apparatus of claim 1 wherein the pre-processing comprises identifying metadata associated with the impending IO.

5. The apparatus of claim 4 wherein the pre-processing comprises using the identified metadata to identify locations in volatile memory associated with the impending IO.

6. The apparatus of claim 5 wherein the pre-processing comprises locking the identified locations.

7. The apparatus of claim 1 further comprising program code that writes the data to the memory at least partly concurrently with the second storage array writing the data to memory.

8. A method comprising:

in a network comprising;

a first storage array comprising a plurality of interconnected computing nodes, each of the computing nodes comprising at least one processor and non-transitory memory, and a plurality of groups of data storage drives, each group of data storage drives connected with one of the computing nodes, wherein the first storage array maintains a first replica of a replicated volume comprising contiguous logical block addresses that map to non-contiguous addresses of the data storage drives; and

a second storage array comprising a plurality of interconnected computing nodes, each of the computing nodes comprising at least one processor and non-transitory memory, and a plurality of groups of data storage drives, each group of data storage drives connected with one of the computing nodes, wherein the second storage array maintains a second replica of the replicated volume comprising contiguous logical block addresses that map to non-contiguous addresses of the data storage drives;

the first storage array generating a notification that an impending IO that will update the replicated volume, the notification comprising information that enables implementation of pre-processing steps to prepare for receipt of data associated with the impending IO;

the first storage array providing the notification to the second storage array; and

the first storage array implementing the pre-processing steps to prepare for receipt of the data associated with the impending IO at least partly concurrently with implementation of the pre-processing steps by the second storage array.

9. The method of claim 8 wherein generating the notification comprises indicating LBAs (logical block addresses) affected by the impending IO.

10. The method of claim 8 wherein generating the notification comprises indicating at least one of:

device number, cylinder number, head (track), and size.

11. The method of claim 8 wherein implementing the pre-processing steps comprises identifying metadata associated with the impending IO.

12. The method of claim 11 wherein implementing the pre-processing steps comprises using the identified metadata to identify locations in volatile memory associated with the impending IO.

13. The method of claim 12 wherein implementing the pre-processing steps comprises locking the identified locations.

14. The method of claim 8 further comprising the first storage array writing the data to the memory at least partly concurrently with the second storage array writing the data to memory.

15. A system comprising:

a first storage array comprising a plurality of interconnected computing nodes, each of the computing nodes comprising at least one processor and non-transitory memory, and a plurality of groups of data storage drives, each group of data storage drives connected with one of the computing nodes, wherein the first storage array maintains a first replica of a replicated volume comprising contiguous logical block addresses that map to non-contiguous addresses of the data storage drives; and

a second storage array comprising a plurality of interconnected computing nodes, each of the computing nodes comprising at least one processor and non-transitory memory, and a plurality of groups of data storage drives, each group of data storage drives connected with one of the computing nodes, wherein the second storage array maintains a second replica of the replicated volume comprising contiguous logical block addresses that map to non-contiguous addresses of the data storage drives;

wherein the first storage array is responsive to a write command from a host to generate a notification that the replicated volume will be updated, the notification comprising information that enables implementation of pre-processing steps to prepare for subsequent receipt of data associated with the write command;

wherein the first storage array provides the notification to the second storage array; and

wherein the first storage array implements the pre-processing steps prior to receipt of the data and at least partly concurrently with implementation of the pre-processing steps by the second storage array.

16. The system of claim 15 wherein the notification indicates LBAs (logical block addresses) affected by the impending IO.

17. The system of claim 15 wherein the pre-processing steps comprise identifying metadata associated with the impending IO.

18. The system of claim 17 wherein the pre-processing steps comprise using the identified metadata to identify locations in volatile memory associated with the impending IO.

19. The system of claim 18 wherein the pre-processing steps comprise locking the identified locations.

20. The system of claim 15 wherein the first storage array writes the data to the memory at least partly concurrently with the second storage array writing the data to memory.