Live Migration Dirty Bitmap Tracking via Selective Status Clearing
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Solution Overview
Problem
In live migration operations, redundant copying occurs due to the use of dirty bitmaps that track subsequent user data writes, leading to inefficiencies and slowdowns in the data migration process.
Innovation Solution
A method is introduced where a storage controller transfers a first data structure to a live migration server, selectively generating or clearing status identifiers in a second data structure based on the current copying location, to track planned and copied sections of the source storage, thereby reducing redundant copying and improving efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dirty bitmaps are used to track subsequent user data writes, then data migration completeness is improved, but redundant copying occurs and migration speed deteriorates
Solution Approach 1:
The patent applies preliminary action by having the storage controller proactively clear dirty bitmap entries corresponding to data sections that have already been copied, before the live migration server attempts to copy them again. This preventive clearing action eliminates redundant copying operations and accelerates the migration process while maintaining data completeness.
2Reliability
If dirty bitmaps track all user data writes, then no data is missed, but the amount of metadata increases and processing overhead increases
Solution Approach 1:
The patent extracts and removes unnecessary dirty bitmap entries from the metadata structure by clearing entries that correspond to already-copied data sections. This extraction reduces the metadata size and simplifies the tracking process, while still maintaining accurate tracking of all uncopied data writes through selective entry management.
3Ease of manufacture
If continuous copying is performed without optimization, then simple processing is used, but energy consumption increases and latency increases
Solution Approach 1:
The patent implements periodic action by having the storage controller periodically clear dirty bitmap entries at strategic points during the migration process, rather than continuously managing them. This periodic optimization reduces unnecessary processing operations, lowers energy consumption, and decreases latency without significantly complicating the overall processing flow.
Data Source
AI summary
A method for tracking a progress of data copying for a live migration includes transferring, by a storage controller, a first data structure to a live migration server, the first data structure including a first status identifier indicating a location of a source data to be copied from a source storage to a target storage, and selectively generating or selectively clearing, by the storage controller, a second status identifier in or from a second data structure, based on a first current copying location of the live migration server, the second status identifier indicating a location of a first user data write to the source storage.