Uninterrupted data flushing in storage systems

Patent metadata

Field	Value
Publication number	US-11687274-B2
Application number	US-202117513126-A
Country	US
Kind code	B2
Filing date	Oct 28, 2021
Priority date	Oct 28, 2021
Publication date	Jun 27, 2023
Grant date	Jun 27, 2023

Abstract

A method is used for uninterrupted data flushing in a storage system. An input/output (I/O) request is received. A pointer for a filling flushing work set (FWS) is atomically switching. A copy of the pointer for the filling FWS is saved, and the counter associated with a FWS referenced by the saved copy of the pointer is incremented. The saved copy of the pointer and the pointer for the filling FWS are compared, and upon determining that the saved copy of the pointer and the pointer for the filling are FWS equal, the I/O request is committed to a page descriptor ring and the counter associated with the FWS referenced by the saved copy of the pointer is decremented.

First claim

What is claimed is:

1. A method for uninterrupted data flushing in a storage system, the method comprising:
receiving an input/output (I/O) request;
atomically switching a pointer for a filling flushing work set (FWS);
saving a copy of the pointer for the filling FWS;
incrementing a counter associated with a FWS referenced by the saved copy of the pointer;
comparing the saved copy of the pointer and the pointer for the filling FWS; and
upon determining that the saved copy of the pointer and the pointer for the filling FWS are equal, committing the I/O request to a page descriptor ring and decrementing the counter associated with the FWS referenced by the saved copy of the pointer.

2. The method of claim 1 , further comprising:
upon determining that the saved copy of the pointer and the pointer for the filling FWS are not equal,
decrementing the counter associated with the FWS referenced by the saved copy of the pointer; and
repeating the steps of saving the copy of the pointer for the filling FWS, incrementing the counter associated with the FWS referenced by the saved copy of the pointer, and comparing the saved copy of the pointer and the pointer for the filling FWS until the saved copy of the pointer and the pointer for the filling FWS are FWS are equal.

3. The method of claim 1 , further comprising:
sending the I/O request and an identification of the filling FWS to a peer node for commitment.

4. The method of claim 1 , further comprising:
monitoring the counter associated with the FWS referenced by the saved copy of the pointer until the counter reaches zero (0); and
when the counter reaches zero (0), flushing data from the FWS referenced by the saved copy of the pointer.

5. The method of claim 4 , further comprising:
sending an instruction to another node to switch the filling FWS.

6. The method of claim 5 , further comprising:
upon confirmation from the other node that its filling FWS has been switched and the counter reaching zero (0), flushing data from the FWS referenced by the saved copy of the pointer.

7. A system for uninterrupted data flushing in a storage system, the system including a processor configured to:
receive an input/output (I/O) request;
atomically switch a pointer for a filling flushing work set (FWS);
save a copy of the pointer for the filling FWS;
increment a counter associated with a FWS referenced by the saved copy of the pointer;
compare the saved copy of the pointer and the pointer for the filling FWS; and
upon determining that the saved copy of the pointer and the pointer for the filling FWS are equal, commit the I/O request to a page descriptor ring and decrementing the counter associated with the FWS referenced by the saved copy of the pointer.

8. The system of claim 7 , wherein the processor is further configured to:
upon determining that the saved copy of the pointer and the pointer for the filling FWS are not equal,
decrement the counter associated with the FWS referenced by the saved copy of the pointer; and
repeat the steps of saving the copy of the pointer for the filling FWS, incrementing the counter associated with the FWS referenced by the saved copy of the pointer, and comparing the saved copy of the pointer and the pointer for the filling FWS until the saved copy of the pointer and the pointer for the filling FWS are equal.

9. The system of claim 7 , wherein the processor is further configured to:
send the I/O request and an identification of the filling FWS to a peer node for commitment.

10. The system of claim 7 , wherein the processor is further configured to:
monitor the counter associated with the FWS referenced by the saved copy of the pointer until the counter reaches zero (0); and
when the counter reaches zero (0), flush data from the FWS referenced by the saved copy of the pointer.

11. The system of claim 10 , wherein the processor is further configured to:
send an instruction to another node to switch the filling FWS.

12. The system of claim 11 , wherein the processor is further configured to:
upon confirmation from the other node that its filling FWS has been switched and the counter reaching zero (0), flush data from the FWS referenced by the saved copy of the pointer.

Assignees

• Dell Products Lp

Inventors

• Han Geng
• Shveidel Vladimir
• Liu Yousheng

Classifications

• G06F3/0655 Primary

  Vertical data movement, i.e. input-output transfer; data movement between one or more hosts and one or more storage devices · CPC title

• G06F3/061

  Improving I/O performance · CPC title

• G06F3/067 Primary

  Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS] · CPC title

• G06F3/0659

  Command handling arrangements, e.g. command buffers, queues, command scheduling · CPC title