Virtual Machine File Compaction via Block Extraction

Solution Overview

Problem

Virtual machine files often waste storage space due to dynamic expansion without shrinking, and existing compaction methods like zero-filling reduce storage device lifespan and performance by increasing write operations.

Innovation Solution

A system and method for compacting virtual machine files by identifying and copying only used blocks to a new file, ignoring unused or zero-filled blocks, thereby reducing the file size without the need for excessive write operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of stationary object

If traditional zero-filling compaction method is used, then virtual machine file size is reduced, but storage device lifespan is reduced and performance deteriorates due to increased write operations

Engineering Contradiction:

Improvevirtual machine file sizeVSAvoidstorage device lifespan

Core Design Contradiction:

Volume of stationary objectVSReliability

Solution Approach 1:

The patent extracts only the used data blocks from the virtual machine file and creates a new compacted file containing only those blocks. By identifying and copying only the blocks that contain actual data (using bitmaps to track used blocks), the system reduces the file size without performing write operations on unused blocks, thereby avoiding wear on the storage device while achieving compaction.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of the traditional approach of filling unused blocks with zeros and then compacting, this patent inverts the process by directly identifying and copying only the used blocks to create the compacted file. This reversal eliminates the need for write operations on unused blocks, solving both the storage waste problem and the storage device wear problem simultaneously.

Inventive Principle:

Principle #13The other way round (Inversion)

2Volume of stationary object

If traditional zero-filling compaction method is used, then virtual machine file size is reduced, but storage device performance deteriorates due to increased write operations

Engineering Contradiction:

Improvevirtual machine file sizeVSAvoidstorage device performance

Core Design Contradiction:

Volume of stationary objectVSProductivity

Solution Approach 1:

The patent extracts only the used data blocks from the virtual machine file and creates a new compacted file containing only those blocks. By identifying and copying only the blocks that contain actual data (using bitmaps to track used blocks), the system reduces the file size without performing write operations on unused blocks, thereby avoiding wear on the storage device while achieving compaction.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of the traditional approach of filling unused blocks with zeros and then compacting, this patent inverts the process by directly identifying and copying only the used blocks to create the compacted file. This reversal eliminates the need for write operations on unused blocks, solving both the storage waste problem and the storage device wear problem simultaneously.

Inventive Principle:

Principle #13The other way round (Inversion)

3Adaptability or versatility

If dynamic expansion is used for virtual machine files, then storage flexibility is improved, but storage space waste increases as files do not shrink when data is removed

Engineering Contradiction:

Improvestorage flexibilityVSAvoidstorage space waste

Core Design Contradiction:

Adaptability or versatilityVSLoss of substance

Solution Approach 1:

The patent extracts only the used data blocks from the virtual machine file and creates a new compacted file containing only those blocks. By identifying and copying only the blocks that contain actual data (using bitmaps to track used blocks), the system reduces the file size without performing write operations on unused blocks, thereby avoiding wear on the storage device while achieving compaction.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent discards the unused blocks from the virtual machine file by not copying them to the new compacted file. The bitmap tracking mechanism identifies which blocks are actually in use, allowing the system to recover storage space by excluding unused blocks from the compacted file, thus eliminating storage space waste while maintaining flexibility.

Inventive Principle:

Principle #34Discarding and recovering

Data Source

PatentUS9311375B1Systems and methods for compacting a virtual machine file

Publication Date: 2016.04.12 QUEST SOFTWARE INC

AI summary

Systems and methods for compacting a virtual machine file are presented. In one example, the system accesses a source virtual machine file associated with a guest file system. The system creates a destination virtual machine file based on the guest file system and initializes a block allocation table of the destination virtual machine file. The system accesses a block allocation table of the source virtual machine file and, for each block of the source virtual machine file, determines whether the block is in use. If so, the system copies the block to the destination virtual machine file and updates the block allocation table of the destination virtual machine file. If not, the system does not copy the block or update the block allocation table of the destination virtual machine file, thereby reducing the destination virtual machine file's size compared to the source virtual machine file's size.