Cas command network replication

• US 8,103,937 B1
• Filed: 03/31/2010
• Issued: 01/24/2012
• Est. Priority Date: 03/31/2010
• Status: Active Grant

• Current Assignee: Emc IP Holding Company LLC (Dell Technologies Inc.)
• Original Assignee: EMC Corporation (Dell Technologies Inc.)
• Inventors: Natanzon, Assaf, Aharoni, Yuval
• Primary Examiner(s): MCCARTHY, CHRISTOPHER S
• Application Number:
  US12/751,748
• Time in Patent Office: 664 Days
• Field of Search: None
• US Class Current: 714/763
• CPC Class Codes: G06F 11/2064 while ensuring consistency
• CPC Class Codes: G06F 11/2071 using a plurality of controllers

Abstract

In an embodiment, a method and computer product is presented for executing a command in a replicated environment comprising a replication appliance and a production site, the method comprising: intercepting the command at a splitter; wherein the command comprises a atomic test and set request.

Claims

1. A method for executing a command in a replicated environment comprising a replication appliance and a production site, the method comprising:

intercepting the command at a splitter;

wherein the command comprises a atomic test and set (ATS) request;

adding meta data associated with the command to a backlog;

sending the meta data to the replication appliance;

determining success of the meta data at the production site;

based on a failure of the meta data,

determining the type of failure;

based on a determination of a failure, executing a failure determination comprising;

determining whether the failure is a command not supported command;

based on a positive determination that the failure is a command not supported, failing the ATS command; and

based on a negative determination that the command is not supported moving the splitter to marking on host (MOH) mode;

based on success of the meta data, proceeding with processing of the command at the production site; and

sending the ATS command to storage.

2. The method of claim 1 further comprising testing the success of the ATS command.

3. The method of claim 2 wherein based on a successful test of the ATS command, a write part of the command is written to the replication appliance.

4. The method of claim 2 wherein based on the test of the ATS command failing with error, the command is declared incomplete and the replication environment begins to mark on host.

5. The method of claim 2 wherein based on the test of the ATS failing with status STATUS_MISCOMPARE, IO is closed in the backlog.

6. A method for executing a command in a replicated environment, the replicated environment running in virtual access mode, the method comprising:

intercepting the command at a splitter;

wherein the command comprises an atomic test and set (ATS) request;

sending read notification to a replication appliance;

reading a block associated with the command on storage;

sending write execution before read command, containing the data read from the storage;

sending the ATS command to the replication appliance; and

checking the status of the command and returning status to a command generator for the ATS command.

7. The method of claim 6 further comprising based on the checking of the status is ok, forwarding the ATS to the user space of the replication appliance memory.

8. The method of claim 7 further comprising based on the checking of the status is ok, holding write before reads IO in the replication appliance memory until notification of ATS data.

9. The method of claim 7 further comprising based on the checking of the status is ok, executing ATS logic;

wherein the read data is based on journal data and the executed write before read data, returning ATS status to the splitter.

10. The method of claim 6 further comprising based on the checking of the status is a failure command in the splitter, determining if the failure is an not supported command failure;

and based on an unknown command failure, notifying failure of the ATS command.

11. The method of claim 6 further comprising based on the checking of the status is not an no supported command failure, retrying to execute the ATS command.

12. A method for executing a command in a replicated environment comprising a replication appliance and a production site, the replicated environment running in target side processing mode, the method comprising:

intercepting the command at a splitter;

wherein the command comprises atomic test and set;

reading from a volume;

sending the data read from the volume to the replication appliance; and

sending the command to the volume.

13. A computer program product for executing a command in a replicated environment comprising a replication appliance and a production site, the replicated environment running in target side processing mode, the program product comprising:

a non-transitory computer-readable storage medium encoded with computer-executable program code enabling;

intercepting the command at a splitter;

wherein the command comprises atomic test and set

reading from a volume;

sending the data read from the volume to the replication appliance; and

sending the command to the volume.

14. A computer program product for executing a command in a replicated environment comprising a replication appliance and a production site, the program product comprising:

a non-transitory computer-readable storage medium encoded with computer-executable program code enabling;

intercepting the command at a splitter;

wherein the command comprises a atomic test and set (ATS) request;

adding meta data associated with the command to a backlog;

sending the meta data to the replication appliance;

determining success of the meta data at the production site;

based on a failure of the meta data,

determining the type of failure;

based on a determination of a failure, executing a failure determination comprising;

determining whether the failure is a command not supported command;

based on a positive determination that the failure is a command not supported, failing the ATS command; and

based on a negative determination that the command is not supported moving the splitter to marking on host (MOH) mode;

based on success of the meta data, proceeding with processing of the command at the production site; and

sending the ATS command to storage.

15. The computer product of claim 14 further comprising testing the success of the ATS command.

16. The computer product of claim 14 wherein based on a successful test of the ATS command, a write part of the command is written to the replication appliance.

17. A computer program product for executing a command in a replicated environment, the replicated environment running in virtual access mode, the program product comprising:

a non-transitory computer-readable storage medium encoded with computer-executable program code enabling;

intercepting the command at a splitter;

wherein the command comprises an atomic test and set (ATS) request;

sending read notification to a replication appliance;

reading a block associated with the command on the storage;

sending write before read command, containing data read from the storage;

sending the ATS command to the replication appliance; and

checking the status of the command and returning status to a command generator for the ATS command.

18. The computer product of claim 17 further comprising based on the checking of the status is ok, forwarding the ATS to user space of the replication appliance memory.

19. The computer product of claim 17 further comprising based on the checking of the status is ok, holding write before reads IO in the replication appliance memory until notification of ATS data.

20. The computer product of claim 17 further comprising based on the checking of the status is ok, executing ATS logic;

wherein the read data is based on journal data and the executed write before read data, returning ATS status to the splitter.