Granted Patent B1

US 11,513,921 · App. 17/386,334 · Granted Nov 29, 2022

Inventors: Sunil Yadav (Bangalore, IN); Shelesh Chopra (Bangalore, IN)

Assignee: EMC IP HOLDING COMPANY LLC

G06F11/1469G06F9/45541G06F11/1435G06F11/1451G06F11/1464

Abstract

Claims (84)

1. A method for data restoration, comprising:

receiving, from a user, instructions to perform a recovery operation;

in response to the instructions:

identifying a writer-key table comprising a first plurality of data entries, wherein each data entry of the first plurality of data entries maps a volume shadow copy service (VSS) writer to at least one recovery-pertinent file-system object key;

obtaining, from the user, a recovery-pertinent writer selection comprising at least one VSS writer;

identifying an object metadata schema comprising a second plurality of data entries, wherein each data entry of the second plurality of data entries maps a recovery-pertinent file-system object key to recovery-pertinent file-system object metadata;

for each given VSS writer specified in the recovery-pertinent writer selection:

performing a first lookup on the writer-key table using the given VSS writer to obtain the at least one recovery-pertinent file-system object key;

performing a second lookup on the object metadata schema using the at least one recovery-pertinent file-system object key to obtain the recovery-pertinent file-system object metadata for at least one recovery-pertinent file-system object; and

restoring, from a backup target and onto a volume host, the at least one recovery-pertinent file-system object based on the recovery-pertinent file-system object metadata.

2. The method of claim 1 , wherein the at least one recovery-pertinent file-system object key comprises at least one backup container record index assigned to the at least one recovery-pertinent file-system object, respectively.

3. The method of claim 2 , wherein the at least one backup container record index serves to index the at least one recovery-pertinent file-system object, respectively, in a backup container stored on the backup target.

4. The method of claim 3 , wherein the backup container is formatted in a common data stream format (CDSF).

5. The method of claim 3 , wherein the recovery-pertinent file-system object metadata for the at least one recovery-pertinent file-system object comprises a backup container offset indicating where in the backup container that data representative of the at least one recovery-pertinent file-system object is located.

6. The method of claim 1 , wherein the at least one recovery-pertinent file-system object had been a responsibility of the given VSS writer while fulfilling at least one selected from a group of recovery operations consisting of a bare-metal recovery (BMR) operation and a system-state recovery (SSR) operation.

7. The method of claim 1 , further comprising:

prior to receiving the instructions to perform the recovery operation:

submitting, to a VSS, a snapshot request to obtain a consistent shadow copy of the at least one recovery-pertinent file system object for each VSS writer specified in a recovery-pertinent writer set;

generating a backup container comprising the consistent shadow copy; and

writing the backup container to the backup target.

8. The method of claim 7 , further comprising:

prior to submitting the snapshot request:

submitting, to the VSS, a writer request to identify the recovery-pertinent writer set comprising a superset of VSS writers, wherein the superset of VSS writers comprises the recovery-pertinent writer selection;

submitting, to the VSS, a writer metadata request to obtain recovery-pertinent writer metadata for each VSS writer specified in the recovery-pertinent writer set; and

parsing the recovery-pertinent writer metadata to produce a writer-object table comprising a third plurality of data entries, wherein each data entry of the third plurality of data entries maps a VSS writer to at least one recovery-pertinent file-system object.

9. The method of claim 8 , further comprising:

while writing the backup container to the backup target:

creating the object metadata schema,

wherein creation of the object metadata schema comprises:

for each recovery-pertinent file-system object specified in the writer-object table:

generating recovery-pertinent file-system object metadata following a write of a portion of the backup container to the backup target,

 wherein the portion of the backup container comprises data representative of the recovery-pertinent file-system object;

identifying, from the recovery-pertinent file-system object metadata, the recovery-pertinent file-system object key for the recovery-pertinent file-system object; and

adding, in the object metadata schema, a data entry comprising the recovery-pertinent file-system object key and the recovery-pertinent file-system object metadata for the recovery-pertinent file-system object.

10. The method of claim 9 , further comprising:

following the creation of the object metadata schema:

generating the writer-key table,

wherein generation of the writer-key table comprises:

for each VSS writer specified in recovery-pertinent writer set:

performing a third lookup on the writer-object table using the VSS writer to identify the at least one recovery-pertinent file-system object;

identifying, from the object metadata schema, at least one recovery-pertinent file-system object key for the at least one recovery-pertinent file-system object, respectively; and

adding, in the writer-key table, a data entry comprising the VSS writer and the at least one recovery-pertinent file-system object key.

11. A non-transitory computer readable medium (CRM) comprising computer readable program code, which when executed by a computer processor, enables the computer processor to perform a method for data restoration, the method comprising:

receiving, from a user, instructions to perform a recovery operation;

in response to the instructions:

identifying a writer-key table comprising a first plurality of data entries, wherein each data entry of the first plurality of data entries maps a volume shadow copy service (VSS) writer to at least one recovery-pertinent file-system object key;

obtaining, from the user, a recovery-pertinent writer selection comprising at least one VSS writer;

identifying an object metadata schema comprising a second plurality of data entries, wherein each data entry of the second plurality of data entries maps a recovery-pertinent file-system object key to recovery-pertinent file-system object metadata;

for each given VSS writer specified in the recovery-pertinent writer selection:

performing a first lookup on the writer-key table using the given VSS writer to obtain the at least one recovery-pertinent file-system object key;

performing a second lookup on the object metadata schema using the at least one recovery-pertinent file-system object key to obtain the recovery-pertinent file-system object metadata for at least one recovery-pertinent file-system object; and

restoring, from a backup target and onto a volume host, the at least one recovery-pertinent file-system object based on the recovery-pertinent file-system object metadata.

12. The non-transitory CRM of claim 11 , wherein the at least one recovery-pertinent file-system object key comprises at least one backup container record index assigned to the at least one recovery-pertinent file-system object, respectively.

13. The non-transitory CRM of claim 12 , wherein the at least one backup container record index serves to index the at least one recovery-pertinent file-system object, respectively, in a backup container stored on the backup target.

14. The non-transitory CRM of claim 13 , wherein the backup container is formatted in a common data stream format (CDSF).

15. The non-transitory CRM of claim 13 , wherein the recovery-pertinent file-system object metadata for the at least one recovery-pertinent file-system object comprises a backup container offset indicating where in the backup container that data representative of the at least one recovery-pertinent file-system object is located.

16. The non-transitory CRM of claim 11 , wherein the at least one recovery-pertinent file-system object had been a responsibility of the given VSS writer while fulfilling at least one selected from a group of recovery operations consisting of a bare-metal recovery (BMR) operation and a system-state recovery (SSR) operation.

17. The non-transitory CRM of claim 11 , the method further comprising:

prior to receiving the instructions to perform the recovery operation:

submitting, to a VSS, a snapshot request to obtain a consistent shadow copy of the at least one recovery-pertinent file system object for each VSS writer specified in a recovery-pertinent writer set;

generating a backup container comprising the consistent shadow copy; and

writing the backup container to the backup target.

18. The non-transitory CRM of claim 17 , the method further comprising:

prior to submitting the snapshot request:

submitting, to the VSS, a writer request to identify the recovery-pertinent writer set comprising a superset of VSS writers, wherein the superset of VSS writers comprises the recovery-pertinent writer selection;

submitting, to the VSS, a writer metadata request to obtain recovery-pertinent writer metadata for each VSS writer specified in the recovery-pertinent writer set; and

parsing the recovery-pertinent writer metadata to produce a writer-object table comprising a third plurality of data entries, wherein each data entry of the third plurality of data entries maps a VSS writer to at least one recovery-pertinent file-system object.

19. The non-transitory CRM of claim 18 , the method further comprising:

while writing the backup container to the backup target:

creating the object metadata schema,

wherein creation of the object metadata schema comprises:

for each recovery-pertinent file-system object specified in the writer-object table:

generating recovery-pertinent file-system object metadata following a write of a portion of the backup container to the backup target,

 wherein the portion of the backup container comprises data representative of the recovery-pertinent file-system object;

identifying, from the recovery-pertinent file-system object metadata, the recovery-pertinent file-system object key for the recovery-pertinent file-system object; and

adding, in the object metadata schema, a data entry comprising the recovery-pertinent file-system object key and the recovery-pertinent file-system object metadata for the recovery-pertinent file-system object.

20. The non-transitory CRM of claim 19 , the method further comprising:

following the creation of the object metadata schema:

generating the writer-key table,

wherein generation of the writer-key table comprises:

for each VSS writer specified in recovery-pertinent writer set:

performing a third lookup on the writer-object table using the VSS writer to identify the at least one recovery-pertinent file-system object;

identifying, from the object metadata schema, at least one recovery-pertinent file-system object key for the at least one recovery-pertinent file-system object, respectively; and

adding, in the writer-key table, a data entry comprising the VSS writer and the at least one recovery-pertinent file-system object key.

Assignments (8)

Priority Claims (1)

Cited By (10)

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