Virtual Machine Storage Balloon Agent for Real-Time Space Release
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Solution Overview
Problem
Existing methods for managing VM storage space are inefficient, particularly in releasing free space, as they involve high operation overhead with many disk read and write operations, and are limited to dynamic allocation formats, failing to provide real-time global free data block information and not applicable to pre-allocation formats.
Innovation Solution
A method and system utilizing a Storage Balloon Agent (SBA) in the VM and a Storage Balloon Daemon (SBD) in the VMM layer to acquire and release virtual storage free block information, allowing real-time identification and release of physical storage space, applicable to both dynamic and pre-allocation formats.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the existing method sets free blocks to zero and scans to identify zero blocks, then free space can be released, but high operation overhead exists with many disk read and write operations
Solution Approach 1:
The patent introduces a balloon device as an intermediary component that occupies virtual storage space without requiring actual data writing. The balloon device acts as a mediator between the VM and the storage system, allowing the host to track and manage free space without performing exhaustive read/write operations on all blocks. This resolves the contradiction by eliminating the need to write zeros to every free block while still enabling effective space management and release.
Solution Approach 2:
The balloon device maintains its own metadata structures (such as block allocation maps) that automatically track which virtual blocks are occupied and which are free. This self-service mechanism allows the system to identify free space without external scanning operations, thereby reducing disk I/O overhead while maintaining accurate space information for release operations.
2Loss of information
If the host indirectly judges space occupation by identifying zero blocks, then free blocks can be found, but global free data block information cannot be acquired in real time
Solution Approach 1:
The balloon device pre-establishes and maintains metadata structures that continuously track the occupation status of virtual storage blocks. Rather than waiting for space to be freed and then scanning to find it, the system performs preliminary tracking of all block allocations in real-time. This allows the host to immediately know which blocks are free without performing time-consuming identification operations, thus acquiring global free data block information in real-time.
3Loss of substance
If dynamic allocation is used to reduce storage resource waste, then storage space is allocated according to requirements, but the host cannot perceive file deletion operations and cannot release free space
Solution Approach 1:
The balloon device implements a feedback mechanism where the VM (through balloon agents) continuously informs the host about its actual storage usage requirements. When the VM deletes files or reduces its storage needs, the balloon device detects this change through its metadata tracking and notifies the host. This feedback loop ensures that the host is always aware of the current free space status and can promptly release unused physical storage resources, resolving the reliability issue while maintaining dynamic allocation benefits.
Data Source
AI summary
A method for managing Virtual Machine (VM) storage space is provided. In the method, a Storage Balloon Agent (SBA) module deployed in a VM is adopted to directly acquire virtual storage free block information and deliver the acquired virtual storage free block information to a Storage Balloon Daemon (SBD) module deployed in a Virtual Machine Monitor (VMM) layer; and the SBD module releases a part or all of physical storage space corresponding to the virtual storage free block information, and marks virtual storage blocks corresponding to the released physical storage space as unavailable. A corresponding system and a physical host are further provided in the present invention. Through the method of an embodiment of the present invention, use condition of virtual storage space can be acquired in real time, and a large number of read and write operations of a storage system can be avoided.