Recovery mechanisms across storage nodes that reduce the impact on host input and output operations

Patent metadata

Field	Value
Publication number	US-9459974-B2
Application number	US-201414289197-A
Country	US
Kind code	B2
Filing date	May 28, 2014
Priority date	May 28, 2014
Publication date	Oct 4, 2016
Grant date	Oct 4, 2016

Abstract

Provided are a method, a system, and a computer program product in which a storage controller determines one or more resources that are impacted by an error. A cleanup of tasks associated with the one or more resources that are impacted by the error is performed, to recover from the error, wherein host input/output (I/O) operations continue to be processed, and wherein tasks associated with other resources continue to execute.

First claim

What is claimed is:

1. A method, comprising:
determining, by a storage controller, one or more resources that are impacted by an error; and
performing a cleanup of tasks associated with the one or more resources that are impacted by the error, to recover from the error, wherein host input/output (I/O) operations continue to be processed, and wherein tasks associated with other resources continue to execute, the method further comprising:
determining whether an impacted resource is in an I/O path;
in response to determining that the impacted resource is in the I/O path, determining whether the impacted resource is currently executing I/O;
in response to determining that the impacted resource is currently executing I/O, performing an I/O recovery sequence; and
in response to determining that the impacted resource is currently not executing I/O, determining whether operations are being performed in a non I/O recovery sequence for the impacted resource.

2. The method of claim 1 , wherein:
no communication is made to tasks associated with other resources to indicate that the cleanup of tasks is being performed; and
no communication is made to a host that has initiated the host I/O operations to indicate that the cleanup of tasks is being performed.

3. The method of claim 1 , wherein:
the cleanup of tasks associated with the one or more resources that are impacted by the error is performed asynchronously.

4. The method of claim 1 , the method further comprising:
in response to determining that operations are not being performed in the non I/O recovery sequence for the impacted resource, starting another non I/O recovery sequence;
in response to determining that operations are being performed in the non I/O recovery sequence for the impacted resource, determining whether the non I/O recovery sequence has reached a point where a new task has been started for the impacted resource; and
in response to determining that the new task has not been started for the impacted resource, continue with execution of the non I/O recovery sequence.

5. The method of claim 4 , the method further comprising:
in response to determining that the new task has been started for the impacted resource, starting the another non I/O recovery sequence.

6. The method of claim 1 , wherein:
in response to determining that the impacted resource is not in the I/O path, determining whether operations are being performed in a non I/O recovery sequence for the impacted resource.

7. A system, comprising:
a memory; and
a processor coupled to the memory, wherein the processor performs operations, the operations comprising:
determining one or more resources that are impacted by an error; and
performing a cleanup of tasks associated with the one or more resources that are impacted by the error, to recover from the error, wherein host input/output (I/O) operations continue to be processed, and wherein tasks associated with other resources continue to execute, the operations further comprising:
determining whether an impacted resource is in an I/O path;
in response to determining that the impacted resource is in the I/O path, determining whether the impacted resource is currently executing I/O;
in response to determining that the impacted resource is currently executing I/O, performing an I/O recovery sequence; and
in response to determining that the impacted resource is currently not executing I/O, determining whether operations are being performed in a non I/O recovery sequence for the impacted resource.

8. The system of claim 7 , wherein:
no communication is made to tasks associated with other resources to indicate that the cleanup of tasks is being performed; and
no communication is made to a host that has initiated the host I/O operations to indicate that the cleanup of tasks is being performed.

9. The system of claim 7 , wherein:
the cleanup of tasks associated with the one or more resources that are impacted by the error is performed asynchronously.

10. The system of claim 7 , the operations further comprising:
in response to determining that operations are not being performed in the non I/O recovery sequence for the impacted resource, starting another non I/O recovery sequence;
in response to determining that operations are being performed in the non I/O recovery sequence for the impacted resource, determining whether the non I/O recovery sequence has reached a point where a new task has been started for the impacted resource; and
in response to determining that the new task has not been started for the impacted resource, continue with execution of the non I/O recovery sequence.

11. The system of claim 10 , the system further comprising:
in response to determining that the new task has been started for the impacted resource, starting the another non I/O recovery sequence.

12. The system of claim 7 , wherein:
in response to determining that the impacted resource is not in the I/O path, determining whether operations are being performed in a non I/O recovery sequence for the impacted resource.

13. A computer program product, the computer program product comprising:
a computer readable storage medium having computer readable program code embodied therewith, the computer readable program code configured to perform operations on a storage controller, the operations comprising:
determining one or more resources that are impacted by an error; and
performing a cleanup of tasks associated with the one or more resources that are impacted by the error, to recover from the error, wherein host input/output (I/O) operations continue to be processed, and wherein tasks associated with other resources continue to execute, the operations further comprising:
determining whether an impacted resource is in an I/O path;
in response to determining that the impacted resource is in the I/O path, determining whether the impacted resource is currently executing I/O;
in response to determining that the impacted resource is currently executing I/O, performing an I/O recovery sequence; and
in response to determining that the impacted resource is currently not executing I/O, determining whether operations are being performed in a non I/O recovery sequence for the impacted resource.

14. The computer program product of claim 13 , wherein:
no communication is made to tasks associated with other resources to indicate that the cleanup of tasks is being performed; and
no communication is made to a host that has initiated the host I/O operations to indicate that the cleanup of tasks is being performed.

15. The computer program product of claim 13 , wherein:
the cleanup of tasks associated with the one or more resources that are impacted by the error is performed asynchronously.

16. The computer program product of claim 13 , the operations further comprising:
in response to determining that operations are not being performed in the non I/O recovery sequence for the impacted resource, starting another non I/O recovery sequence;
in response to determining that operations are being performed in the non I/O recovery sequence for the impacted resource, determining whether the non I/O recovery sequence has reached a point where a new task has been started for the impacted resource; and
in response to determining that the new task has not been started for the impacted resource, continue with execution of the non I/O recovery sequence.

17. The computer program product of claim 13 , wherein:
in response to determining that the impacted resource is not in the I/O path, determining whether opera

Assignees

• IBM

Inventors

• He Wang Ping
• Juarez Larry
• Kalos Matthew J
• Mccauley John N
• Rasor Louis A
• Rinaldi Brian A
• Sorenson Todd C

Classifications

• G06F11/2017

  where memory access, memory control or I/O control functionality is redundant (redundant communication control functionality G06F11/2005; redundant storage control functionality G06F11/2089) · CPC title

• G06F11/0745

  in an input/output transactions management context (input/output processing in general G06F13/00) · CPC title

• G06F11/0751

  Error or fault detection not based on redundancy (power supply failures G06F1/30; network fault management H04L41/06) · CPC title

• G06F11/0793 Primary

  Remedial or corrective actions (recovery from an exception in an instruction pipeline G06F9/3861; by retry G06F11/1402; for recovering from a failure of a protocol instance or entity H04L69/40) · CPC title

• G06F11/2094 Primary

  Redundant storage or storage space (G06F11/2056 takes precedence) · CPC title