Snapshot Performance via Change Block Tracking
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Solution Overview
Problem
Current data backup technologies face challenges in efficiently managing snapshots for multiple virtual machines, leading to increased resource usage and prolonged snapshot durations due to the need for quiescing, snapshotting, and merging delta data, which degrades performance.
Innovation Solution
Implementing change block tracking for each unit of storage associated with virtual machines, allowing independent snapshot creation and release, and editing backup images to ensure consistency, thereby reducing the time snapshots are maintained and minimizing resource impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If snapshots are maintained until all backup images are created for multiple virtual machines, then backup consistency is ensured, but snapshot duration increases and resource usage increases
Solution Approach 1:
The patent divides the backup process into independent per-virtual-machine operations. Each virtual machine's snapshot is created, backed up, and released independently rather than maintaining all snapshots until complete backup of all VMs. This segmentation allows snapshots to be released sooner while maintaining consistency for each individual VM's backup.
Solution Approach 2:
The patent performs preliminary actions by creating backup images before releasing snapshots. Change block tracking is initiated early to identify modified blocks, and backup images are created while the snapshot is still active. This allows the snapshot to be released immediately after backup image creation without waiting for other VMs, reducing snapshot duration while ensuring consistency.
2Reliability
If multiple snapshots are maintained simultaneously for multiple virtual machines, then backup completeness is ensured, but resource usage (I/O and CPU) increases during merge operations
Solution Approach 1:
The patent segments the backup operations so that each virtual machine is processed independently. Snapshots are created and released per VM rather than maintaining all snapshots simultaneously. This reduces the number of concurrent merge operations and associated resource usage while ensuring each VM's backup is complete and consistent.
Solution Approach 2:
The patent performs preliminary change block tracking to identify only the blocks that need to be backed up. By knowing exactly which blocks are modified before the snapshot is released, the system can efficiently create backup images without needing to maintain snapshots longer or perform extensive merge operations, thereby reducing resource usage.
3Reliability
If delta data is merged back into virtual disks after snapshot release, then data consistency is restored, but I/O demands increase significantly
Solution Approach 1:
The patent performs preliminary change block tracking to identify modified blocks before the snapshot is released. This allows the system to create accurate backup images of only the necessary blocks without requiring extensive merge operations afterward, significantly reducing I/O demands while maintaining data consistency.
Solution Approach 2:
The patent extracts only the changed blocks identified by change block tracking for inclusion in backup images. Rather than merging all delta data back into virtual disks, the system selectively extracts and backs up only the necessary modified blocks, reducing I/O demands during both backup and merge operations while ensuring data consistency.
Data Source
AI summary
Techniques for improving snapshot performance are disclosed. In one embodiment, the techniques may be realized as a method for improving snapshot performance comprising initiating change block tracking for each unit of storage associated with each of a plurality of virtual machines, creating backup images of each unit of storage associated with each of the plurality of virtual machines, quiescing each of the plurality of virtual machines, and creating snapshots of each unit of storage associated with each of the plurality of virtual machines. The techniques may include identifying one or more changed blocks in at least one of the backup images using the change block tracking, editing the at least one of the backup images by replacing the identified one or more changed blocks using corresponding blocks from at least one snapshot of the snapshots, and releasing the at least one snapshot based upon a determination that editing has completed.