Cluster Writer Freeze Command for Application Consistent Snapshots
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Solution Overview
Problem
In distributed computing environments, existing backup systems fail to create application-consistent snapshots across multiple nodes in a cluster, leading to incomplete data capture and the need for separate snapshot initiation on each node.
Innovation Solution
A method and system where a backup coordinator sends a freeze command to cluster writers on all nodes, ensuring all applications persist data before creating a snapshot, and cluster services coordinate to initiate the snapshot process, ensuring application consistency across the cluster.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a snapshot is created on a single node in the cluster, then the snapshot creation process is simple and fast, but the snapshot is not application-consistent across all nodes in the cluster
Solution Approach 1:
The system segments the snapshot coordination task by introducing node-specific cluster writers and cluster services on each node, while maintaining a centralized backup coordinator. Each node's cluster writer independently manages freeze commands for local applications, and cluster services coordinate inter-node communication. This segmentation allows application-consistent snapshots across the cluster without requiring complex centralized control of all node operations.
Solution Approach 2:
The invention introduces cluster writers and cluster services as intermediary components between the backup coordinator and applications on each node. These intermediaries translate the backup coordinator's freeze command into node-specific actions, ensuring that all applications across the cluster persist data before the snapshot is created. The intermediaries handle the complexity of coordinating multiple nodes while presenting a simple interface to the backup system.
2Manufacturing precision
If separate snapshot initiation is performed on each node, then application consistency across the cluster is achieved, but the backup process time and system overhead increase significantly
Solution Approach 1:
The backup coordinator sends a freeze command to cluster writers on all nodes before initiating the actual snapshot creation. This preliminary action causes all applications across the cluster to persist their data to storage before the snapshot is taken. By performing this data persistence action in advance, the system ensures application consistency without requiring separate snapshot initiations on each node, thereby reducing total backup time.
Solution Approach 2:
The invention merges the snapshot initiation process into a single centralized operation at the backup coordinator, which then propagates freeze commands to all nodes simultaneously. Instead of each node independently initiating snapshots, the system combines coordination logic at the backup coordinator level while using distributed cluster writers to execute the freeze action. This merging eliminates redundant operations and reduces overall backup process time while maintaining application consistency.
3Manufacturing precision
If existing backup systems are used without modification, then system simplicity is maintained, but application-consistent snapshots across multiple nodes cannot be created
Solution Approach 1:
The invention introduces cluster writers and cluster services that serve multiple functions: they coordinate freeze commands from the backup coordinator, manage local application data persistence, and communicate snapshot status across the cluster. These multi-functional components are integrated into the existing backup system architecture, allowing the system to create application-consistent snapshots across multiple nodes while maintaining compatibility with existing backup workflows and minimizing architectural changes.
Data Source
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AI summary
The present invention extends to methods, systems, and computer program products for creating a snapshot of a shared volume that is application consistent across various nodes of a cluster. The invention enables a snapshot of a volume to be initiated on one node which causes all applications in the cluster that use the volume to persist their data to the volume prior to the snapshot being created. Accordingly, the snapshot is application consistent to all applications in the cluster that use the volume. The invention also enables applications on various nodes to perform post snapshot processing on the created snapshot. The invention can be used in an existing backup system that is not cluster aware to enable the existing backup system to create application consistent snapshots of a volume shared by applications across multiple nodes of a cluster.