File System Changed Block Tracking Using Volume CBT Mapping
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Solution Overview
Problem
Existing file system changed block tracking (FS CBT) methods are unreliable during server reboots due to file system detachment, leading to significant computing resource consumption and degraded user experience from full volume scans.
Innovation Solution
Leveraging volume level CBT to track changes reliably by interfacing with the file system to identify file mapping information, allowing for more accurate FS CBT without full volume scans.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If full volume scans are performed to ensure reliable FS CBT during reboots, then reliability of backup tracking is improved, but computing resource consumption increases
Solution Approach 1:
The patent segments the backup tracking process into two levels: volume-level CBT (performed by the data platform) and file-system-level CBT (performed by the agent). This segmentation allows the agent to leverage the more reliable volume-level tracking data instead of performing full volume scans, thus maintaining reliability while reducing computing resource consumption during reboots.
Solution Approach 2:
The patent implements preliminary action by having the data platform perform volume-level CBT tracking continuously in the background before reboots occur. This pre-established tracking data is then available to the agent after reboot, eliminating the need for post-reboot full volume scans and reducing computing resource consumption while maintaining reliability.
2Measurement precision
If full volume scans are performed after reboot to track file changes, then measurement precision of changed blocks is improved, but productivity decreases
Solution Approach 1:
The patent introduces volume-level CBT data as an intermediary between the file system and the backup agent. Instead of directly scanning volumes to identify changed blocks, the agent uses the volume-level CBT tracking data maintained by the data platform as an intermediary layer, achieving accurate changed block identification with reduced processing time and improved productivity.
3Adaptability or versatility
If FS CBT is implemented independently without volume level CBT support, then adaptability to different file systems is improved, but reliability of tracking during reboots deteriorates
Solution Approach 1:
The patent merges FS CBT and volume level CBT by having the agent leverage the data platform's volume-level CBT tracking capability. This combination allows the system to maintain file-system-level adaptability while achieving volume-level tracking reliability during reboots, as the agent can query volume-level CBT data that persists across reboots.
Data Source
AI summary
A computing device comprising a storage device and processing circuitry may perform the techniques of this disclosure. The storage device may have a plurality of blocks forming a volume. The processing circuitry may obtain volume changed block tracking (CBT) information identifying one or more of the blocks storing updated data that has changed relative to a previous backup of the one or more blocks, and determine file mapping information identifying one or more blocks of the plurality of blocks that store file data associated with a file. The processing circuitry may also determine, based on the volume CBT information and the file mapping information, file system CBT information identifying whether at least one of the one or more blocks store file data associated with the file have changed, and initiate, based on the file system CBT information, a subsequent backup of at least a portion of the file data.