Virtual Disk Incremental Backup via Change Tracking
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Solution Overview
Problem
Existing data backup methods for virtual disks with expandable sizes are inefficient as they require full backups, leading to excessive data transmission and duplication, whereas incremental backups are only applicable to fixed-size virtual disks.
Innovation Solution
A method that obtains information about data changes in a virtual disk, determines the location and size changes, and generates incremental backup data by referencing unchanged blocks and including only changed data, reducing the amount of data to be backed up.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If full backup is performed for virtual disk with expandable size, then all data is backed up ensuring completeness, but large amount of duplicate data is transmitted increasing network cost and time
Solution Approach 1:
The patent extracts only the changed data blocks from the virtual disk for backup, rather than backing up the entire disk image. The backup system identifies modified blocks through change tracking information and transmits only these specific blocks to the backup server, eliminating the transmission of unchanged duplicate data while ensuring all changes are captured.
Solution Approach 2:
The patent implements partial backup by performing incremental backup of only the changed portions of the virtual disk. Instead of complete backup actions, the system performs partial backup actions targeting specifically the modified blocks, reducing the overall backup data volume while maintaining backup effectiveness for expandable virtual disks.
2Loss of energy
If incremental backup is performed for changed data, then data transmission is reduced, but it is applicable only to fixed size virtual disks not expandable ones
Solution Approach 1:
The patent creates a universal backup solution that works for both fixed-size and expandable virtual disks. The backup system monitors virtual disk size changes and dynamically adjusts the backup process: for fixed-size disks it performs traditional incremental backup, while for expandable disks it handles size expansion by backing up new blocks and updating the backup metadata, thus achieving multi-functionality across different virtual disk types.
Solution Approach 2:
The patent implements dynamic backup adaptation where the backup system continuously monitors the virtual disk size and adjusts the backup strategy accordingly. When the virtual disk expands, the system dynamically incorporates new blocks into the backup process, updating the backup image size and block mappings to reflect the changed disk structure, enabling incremental backup to work seamlessly with expandable disks.
3Reliability
If full backup is performed every time data changes, then backup reliability is maintained, but backup time increases significantly
Solution Approach 1:
The patent performs preliminary actions by maintaining change tracking information that records which blocks have been modified before the backup process is initiated. This preliminary tracking of data changes allows the backup system to quickly identify and backup only the changed blocks without scanning or verifying the entire virtual disk, significantly reducing backup time while ensuring all changes are captured reliably.
Data Source
AI summary
Embodiments of the present disclosure provide a method, apparatus and computer program product for data backup. A method includes obtaining first information about data change in a virtual disk, where the first information indicates that data in at least one block of a plurality of blocks is changed. The method also includes determining, based on the first information, second information about a location of the at least one block in the virtual disk. The method further includes obtaining a first size of the virtual disk backed up to a backup server prior to the data change and a second size of the virtual disk subsequent to the data change. In addition, the method includes generating, based on the second information, the first size and the second size, incremental backup data for backing up the virtual disk having the second size to the backup server.