VM Live Migration Reducing Network Bandwidth via Laundered Page Exclusion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Virtual machine live migration is constrained by network throughput due to redundant transmissions of laundered memory pages, especially when multiple virtual machines are migrated concurrently.
Innovation Solution
A data structure is maintained by the virtual machine to map memory page addresses to virtual disk frames, with a page modification flag indicating changes, allowing the migration agent to transmit only modified or missing pages over the network, thereby excluding redundant transmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If all memory pages are transmitted during virtual machine live migration, then the destination host receives complete memory state, but redundant transmissions occur for pages already laundered to virtual disk
Solution Approach 1:
The patent extracts and excludes laundered memory pages from the transmission set by maintaining a data structure that maps virtual disk frames to memory pages. The migration agent queries this data structure to identify pages already persisted to virtual disk and excludes them from network transmission, thereby removing redundant data transfer while preserving complete memory state for non-laundered pages
Solution Approach 2:
The virtual machine performs preliminary laundering of memory pages to virtual disk before migration completes. The data structure is pre-populated with mappings of laundered pages, enabling the migration agent to proactively identify and exclude these pages from transmission before the actual migration data transfer begins, optimizing network bandwidth usage
2Productivity
If multiple virtual machines are migrated concurrently, then resource utilization improves, but network throughput becomes constrained due to redundant transmissions
Solution Approach 1:
For each concurrently migrating virtual machine, the migration agent queries the data structure to extract and exclude laundered pages from transmission. This per-VM exclusion mechanism scales across multiple concurrent migrations, preventing cumulative redundant traffic from overwhelming network throughput while maintaining high concurrent migration capacity
Solution Approach 2:
Instead of transmitting all memory pages for each virtual machine, the system performs partial transmission by sending only non-laundered pages. The data structure enables precise identification of the subset of pages requiring transmission, reducing network load proportionally to the number of laundered pages across all concurrent migrations
3Loss of energy
If a data structure mapping memory pages to virtual disk frames is maintained, then redundant transmissions are excluded, but additional memory overhead is introduced
Solution Approach 1:
The data structure is maintained locally within the virtual machine's address space rather than as a separate global structure. By integrating the mapping information into the VM's existing memory management structures, the patent minimizes additional memory overhead while enabling efficient identification of laundered pages for exclusion from transmission
Data Source
AI summary
Systems and methods for reducing redundant network transmissions in virtual machine live migration. An example method may comprise: reading, by a hypervisor running on a first computer system, from a memory mapped into an address space of a virtual machine undergoing live migration from the first computer system to a second computer system, a data structure comprising a plurality of records, each record mapping an address of a memory page to an identifier of a virtual disk frame storing contents of the memory page; reading a plurality of page modification flags, each page modification flag indicating that contents of a corresponding memory page differ from contents of a virtual disk frame referenced by the data structure; responsive to determining that a memory page is referenced by the data structure and that a page modification flag corresponding to the memory page is set, transmitting the memory page to the second computer system; and responsive to determining that a memory page is not referenced by the data structure, transmitting the memory page to the second computer system.