Stream level uninterrupted backup operation using an interrupt service routine approach

Patent metadata

Field	Value
Publication number	US-2020409799-A1
Application number	US-201916454654-A
Country	US
Kind code	A1
Filing date	Jun 27, 2019
Priority date	Jun 27, 2019
Publication date	Dec 31, 2020
Grant date	—

Abstract

Embodiments are described for performing an uninterrupted backup in a storage system in view of one or more abort events. A backup agent receives writes one or more data blocks to a write latch. A parent interrupt service routine (ISR) polls for abort events. In response to an abort event, an intermediate interrupt is generated that spawns a child processes for each process of the backup. The intermediate ISR logs each child ISR, the process it is responsible for, and the intermediate interrupt, for later restoration of the backup state. After a recovery of the above event, then each child ISR can be called to restore its state. After restoring the state, the backup agent resumes the backup from where the abort event was detected. The child ISRs are re-entrant. If another abort event is detected, the backup state can again be saved and later resumed from that state.

First claim

1 . A method of performing uninterrupted backups in view of one or more unexpected abort events, the method comprising:
in response to a backup agent receiving one or more data packets to be backed up, invoking a parent interrupted service routine (ISR) that polls for an unexpected abort event; writing the received data packets to a write latch communicatively coupled to a target storage; in response to receiving the unexpected abort event, saving a state of a plurality of backup processes; restoring the saved state and a future time, and completing the backup.

2 . The method of claim 1 , further comprising:
masking the parent ISR; and stopping backup agent writes to the write latch.

3 . The method of claim 1 , wherein saving a state of the plurality of backup processes comprises:
generating a re-entrant child ISR for each backup process in the plurality of backup processes; and calling each child ISR to hold a current state of the backup process.

4 . The method of claim 3 , further comprising:
calling an intermediate ISR that, for each child ISR, logs the current state of the backup process in the plurality of backup processes, in association with the intermediate interrupt.

5 . The method of claim 4 , further comprising:
querying the intermediate ISR to fetch details of the current state of the plurality of backup processes; calling each child ISR to enforce the fetched current state of a backup process in the plurality of backup processes;

6 . The method of claim 5 , further comprising:
notifying the backup agent that the child ISRs have each enforced the current state of a backup process in the plurality of processes; and instructing the backup agent to resume receiving data packets and writing data packets to the write latch.

7 . The method of claim 4 , further comprising:
receiving a second unexpected abort event; and calling each re-entrant child ISR a second time to save a state for each backup process of a second plurality of backup processes.

8 . A non-transitory computer-readable medium programmed with executable instructions that, when executed by a processing system having at least one hardware processor, perform operations of performing uninterrupted backups in view of one or more unexpected abort events, the operations comprising:
in response to a backup agent receiving one or more data packets to be backed up, invoking a parent interrupted service routine (ISR) that polls for an unexpected abort event; writing the received data packets to a write latch communicatively coupled to a target storage; in response to receiving the unexpected abort event, saving a state of a plurality of backup processes; restoring the saved state and a future time, and completing the backup.

9 . The medium of claim 8 , the operations further comprising:
masking the parent ISR; and stopping backup agent writes to the write latch.

10 . The medium of claim 8 , wherein saving a state of the plurality of backup processes comprises:
generating a re-entrant child ISR for each backup process in the plurality of backup processes; and calling each child ISR to hold a current state of the backup process.

11 . The medium of claim 10 , further comprising:
calling an intermediate ISR that, for each child ISR, logs the current state of the backup process in the plurality of backup processes, in association with the intermediate interrupt.

12 . The medium of claim 11 , the operations comprising:
querying the intermediate ISR to fetch details of the current state of the plurality of backup processes; calling each child ISR to enforce the fetched current state of a backup process in the plurality of backup processes;

13 . The medium of claim 12 , the operations further comprising:
notifying the backup agent that the child ISRs have each enforced the current state of a backup process in the plurality of processes; and instructing the backup agent to resume receiving data packets and writing data packets to the write latch.

14 . The medium of claim 11 , the operations further comprising:
receiving a second unexpected abort event; and calling each re-entrant child ISR a second time to save a state for each backup process of a second plurality of backup processes.

15 . A system comprising:
a processing system having at least one hardware processor, the processing system coupled to a memory programmed with executable instructions that, when executed by the processing system, perform operations of performing uninterrupted backups in view of one or more unexpected abort events, the operations comprising: in response to a backup agent receiving one or more data packets to be backed up, invoking a parent interrupted service routine (ISR) that polls for an unexpected abort event; writing the received data packets to a write latch communicatively coupled to a target storage; in response to receiving the unexpected abort event, saving a state of a plurality of backup processes; and restoring the saved state and a future time, and completing the backup.

16 . The system of claim 15 , the operations further comprising:
masking the parent ISR; and stopping backup agent writes to the write latch.

17 . The system of claim 15 , wherein saving a state of the plurality of backup processes comprises:
generating a re-entrant child ISR for each backup process in the plurality of backup processes; and calling each child ISR to hold a current state of the backup process.

18 . The system of claim 17 , the operations further comprising:
calling an intermediate ISR that, for each child ISR, logs the current state of the backup process in the plurality of backup processes, in association with the intermediate interrupt.

19 . The system of claim 18 , the operations comprising:
querying the intermediate ISR to fetch details of the current state of the plurality of backup processes; calling each child ISR to enforce the fetched current state of a backup process in the plurality of backup processes;

20 . The system of claim 19 , the operations further comprising:
notifying the backup agent that the child ISRs have each enforced the current state of a backup process in the plurality of processes; and instructing the backup agent to resume receiving data packets and writing data packets to the write latch.

21 . The system of claim 18 , the operations further comprising:
receiving a second unexpected abort event; and calling each re-entrant child ISR a second time to save a state for each backup process of a second plurality of backup processes.

Assignees

• Emc Ip Holding Co Llc

Inventors

• Reddy A V Mahesh
• Chetan Battal
• Ambaljeri Mahantesh
• Shankar Dh Swaroop

Classifications

• G06F13/24 Primary

  using interrupt (G06F13/32 takes precedence) · CPC title

• G06F11/1469

  Backup restoration techniques · CPC title

• G06F11/1466 Primary

  to make the backup process non-disruptive · CPC title

• G06F11/0772

  Means for error signaling, e.g. using interrupts, exception flags, dedicated error registers · CPC title

• G06F11/0727

  in a storage system, e.g. in a DASD or network based storage system (drivers for digital recording or reproducing units G06F3/06; circuits for error detection or correction within digital recording or reproducing units G11B20/18; for distributed storage of data in networks, e.g. transport arrangements for network file system [NFS], storage area networks [SAN] or network attached storage [NAS], H04L67/1097) · CPC title