Method and system of performing incremental SQL server database backups

Patent metadata

Field	Value
Publication number	US-9703640-B2
Application number	US-201414159235-A
Country	US
Kind code	B2
Filing date	Jan 20, 2014
Priority date	Jan 7, 2011
Publication date	Jul 11, 2017
Grant date	Jul 11, 2017

Abstract

A system, method, and medium for performing incremental backups of a Microsoft SQL server database. A snapshot of the database is created, and then a map identifying the changed extents is retrieved from the snapshot. The changed extents are then retrieved from the snapshot and stored in a backup storage device. For a restore operation, a full database backup file is written to a storage device and then the changed extents from a stored incremental backup file may be merged with the full backup file. Next, the database server is notified of the reconstructed file and then the reconstructed file is mounted by the database server as a live instance of the database.

First claim

What is claimed is:

1. A method for performing an incremental backup of a database, the method comprising:
performing the incremental backup by conveying a request to a database server to perform a full backup of the database;
in response to said request to perform the full backup:
taking a snapshot of the database, the snapshot comprising a copy of a full image of the database;
retrieving one or more maps from the snapshot, said one or more maps including an identification of data which has changed since a prior backup, wherein the one or more maps include a differential change map (DCM) comprising a bitmap which indicates all data that has changed since the prior backup, a global allocation map comprising information about data extents that have been allocated, a shared global allocation map comprising information about mixed extents that have at least one unused page, and an index allocation map comprising information about extents that a table or index uses;
reading the one or more maps to determine if changed extents are allocated; and
retrieving the changed extents only if they are allocated;
retrieving the changed data utilizing the DCM to identify the changed data;
storing the changed data as an incremental backup file in a storage device; and
storing a copy of said one or more maps in association with the incremental backup file in the storage device;
wherein a schema of the database is automatically generated by querying the database when the prior backup is performed.

2. The method as recited in claim 1 , wherein in response to said request to perform the full backup, the method further comprises:
discarding said snapshot of the database; and
resetting the DCM to indicate no changed data as though a full backup operation was performed when the incremental backup file is stored in the storage device.

3. The method as recited in claim 1 , further comprising:
detecting a request corresponding to said incremental backup file to perform a restore operation;
identifying a full database backup file associated with the incremental backup file;
creating a restored database by performing a restore operation using the incremental backup file and the full database backup file associated with the incremental backup file; and
notifying a database server of the restored database.

4. The method as recited in claim 1 , further comprising:
identifying a previously stored full backup;
retrieving a map associated with the previously stored full backup;
utilizing said map to identify particular data which has changed since a backup performed prior to the previously stored full backup;
storing the particular data as part of a compressed version of the previously stored full backup; and
discarding data of the previously stored full backup which has not changed since the backup performed prior to the previously stored full backup.

5. A non-transitory computer readable storage medium comprising program instructions to perform an incremental backup of a database, wherein when executed the program instructions are configured to:
perform the incremental backup by conveying a request to perform a full backup of the database;
in response to said request to perform the full backup:
take a snapshot of the database, the snapshot comprising a copy of a full image of the database;
retrieve one or more maps from the snapshot, said one or more maps including an identification of data which has changed since a prior backup, wherein the one or more maps include a differential change map (DCM) comprising a bitmap which indicates all data that has changed since the prior backup, a global allocation map comprising information about data extents that have been allocated, a shared global allocation map comprising information about mixed extents that have at least one unused page, and an index allocation map comprising information about extents that a table or index uses;
read the one or more maps to determine if changed extents are allocated; and
retrieve the changed extents only if they are allocated;
retrieve the changed data utilizing the DCM to identify the changed data;
store the changed data as an incremental backup file in a storage device; and
store a copy of said one or more maps in association with the incremental backup file in the storage device;
wherein a schema of the database is automatically generated by querying the database when the prior backup is performed.

6. The non-transitory computer readable storage medium as recited in claim 5 , wherein in response to said request to perform the full backup the program instructions are further configured to:
discard said snapshot of the database; and
resetting the DCM to indicate no changed data as though a full backup operation was performed when the incremental backup file is stored in the storage device.

7. The non-transitory computer readable storage medium as recited in claim 5 , wherein the program instructions are further configured to:
detect a request corresponding to said incremental backup file to perform a restore operation;
identify a full database backup file associated with the incremental backup file;
create a restored database by performing a restore operation using the incremental backup file and the full database backup file associated with the incremental backup file; and
notify a database server of the restored database.

8. The non-transitory computer readable storage medium as recited in claim 7 , wherein the program instructions are further configured to:
identify a previously stored full backup;
retrieve a map associated with the previously stored full backup;
utilize said map to identify particular data which has changed since a backup performed prior to the previously stored full backup;
store the particular data as part of a compressed version of the previously stored full backup; and
discard data of the previously stored full backup which has not changed since the backup performed prior to the previously stored full backup.

9. A system for performing an incremental backup of a database, the system comprising:
a database server;
a media server;
a database; and
one or more storage devices;
wherein in response to a request to perform a full backup, the database server is configured to:
perform the incremental backup using a request to initiate a full backup; and
wherein the media server is configured to:
take a snapshot of the database, the snapshot comprising a copy of a full image of the database;
retrieve one or more maps from the snapshot, said one or more maps including an identification of data which has changed since a prior backup, wherein the one or more maps include a differential change map (DCM) comprising a bitmap which indicates all data that has changed since the prior backup, a global allocation map comprising information about data extents that have been allocated, a shared global allocation map comprising information about mixed extents that have at least one unused page, and an index allocation map comprising information about extents that a table or index uses;
read the one or more maps to determine if changed extents are allocated; and
retrieve the changed extents only if they are allocated;
retrieve the changed data utilizing said DCM to identify the changed data;
store the changed data as an incremental backup file in a storage device; and
store a copy of said one or more maps in association with the incremental backup file in the storage device;
wherein a schema of the database is automatically generated by querying the database when the prior backup is performed.

10. The system as recited in claim 9 , wherein in response to said request to perform the

Assignees

• Veritas Technologies Llc

Inventors

• Beatty Louis J
• Payne Michael A
• Devos Steven R
• Saraf Deepak

Classifications

• G06F11/1451 Primary

  by selection of backup contents · CPC title

• G06F16/128

  Details of file system snapshots on the file-level, e.g. snapshot creation, administration, deletion (error detection or correction of the data by redundancy in operations or in hardware G06F11/14, G06F11/16) · CPC title

• G06F2201/80

  Database-specific techniques · CPC title

• G06F2201/84

  Using snapshots, i.e. a logical point-in-time copy of the data · CPC title

• G06F11/1469

  Backup restoration techniques · CPC title