Data backup and recovery in a data processing system
AssigneeInternational Business Machines Corporation
InventorsStephen M. Baker, Peter J. Lupton
Life of this patent
Estimating the term…
Abstract
A data processing system for managing stored data is described. A log recording incremental updates to the data is provided for data recovery purposes in the event of a system failure. A backup copy of at least a portion of the stored data can be made without closing that portion for update. Any in-progress modifications at the time the backup is taken are allowed for by calculating a recovery point before the time of the backup, from which point recovery is to be performed using the recovery log. The recovery point depends at least in part on the start time of the oldest in-progress data file update.
Claims16
Data processing apparatus comprising:
- means for processing stored data as a series of logical units of work (LUWs), with updates to the stored data made during each LUW being committed at a commit point for that LUW;
- means for maintaining a log of updates made to the stored data:
- means for detecting the oldest uncommitted update made to the stored data;
- means responsive to the detecting means for calculating a recovery point;
- means for taking a backup copy of at least a portion of the stored data while that portion is available for update;
- and
- means for recovering the database by reinstating the backup copy to provide a working copy and applying the updates contained in any log entries made after said recovery point.
A method of operation of a data processor, comprising the steps of:
- processing stored data as a series of logical units of work (LUWs), with updates to the stored data made during each LUW being committed at a commit point for that LUW;
- maintaining a log of updates made to the stored data;
- detecting the oldest uncommitted update made to the stored data;
- calculating a recovery point dependent upon the start time of the oldest uncommitted update;
- taking a backup copy of at least a portion of the stored data while that portion is available for update;
- and
- when necessary, recovering the database by reinstating the backup copy to provide a working copy and applying the updates contained in any log entries made after said recovery point.
A transaction management system having
- means for processing stored data as a series of logical units of work (LUWs), with updates to the stored data made during each LUW being committed at a commit point for that LUW;
- means for maintaining a log of updates made to the stored data;
- means for detecting the oldest uncommitted update made to the stored data:
- means responsive to the detecting means for calculating a recovery point;
- means for taking a backup copy of at least a portion of the stored data while that portion is available for update;
- and
- means for recovering the database by reinstating the backup to provide a working copy and applying the updates contained in any log entries made after said recovery point.
A transaction manager, for cooperating with a data processing apparatus, to provide means for
- processing stored data as a series of logical units of work (LUWs), with updates to the stored data made during each LUW being committed at a commit point for that LUW;
- maintaining a log of updates made to the stored data;
- detecting the oldest uncommitted update made to the stored data;
- calculating a recovery point dependent upon the start time of the oldest uncommitted update;
- taking a backup copy of at least a portion of the stored data while that portion is available for update;
- and
- when necessary, recovering the database by reinstating the backup copy and applying the updates contained in any log entries made after said recovery point.
Apparatus cooperable with data processing apparatus to provide means for
- processing stored data as a series of logical units of work (LUWs), with updates to the stored data made during each LUW being committed at a commit point for that LUW;
- maintaining a log of updates made to the stored data;
- detecting the oldest uncommitted update made to the stored data;
- calculating a recovery point dependent upon the start time of the oldest uncommitted update:
- taking a backup copy of at least a portion of the stored data while that portion is available for update;
- and
- when necessary, recovering tile database by reinstating the backup copy to provide a working copy and applying the updates contained in any log entries made after said recovery point.
Dependencies are inferred from the claim text.