Distributed Consistency Verification for Clustered File Systems
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Solution Overview
Problem
Existing clustered file systems face challenges in ensuring consistency and performance due to the overhead of offline verification processes, which can lead to prolonged unavailability and inconsistencies across striped volume sets.
Innovation Solution
A system and method for distributed consistency verification of a clustered file system, where modified storage operating system functions, such as Load_Inode and Load_Buffer, perform verification procedures before returning objects, ensuring local and distributed consistency checks to maintain file system stability and usability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If offline verification processes are used to ensure file system consistency, then consistency is improved, but system availability deteriorates due to prolonged unavailability
Solution Approach 1:
The verification process is performed preliminarily by loading and verifying inodes and buffer trees from disk into memory before they are needed for file system operations. This advance verification ensures consistency checks are completed beforehand, allowing the file system to remain online and available while maintaining consistency guarantees.
Solution Approach 2:
A verification cache structure is introduced as an intermediary between the disk storage and the file system operations. This cache holds pre-verified inode and buffer tree data, mediating between the need for consistency verification and the need for system availability by providing quickly accessible, pre-checked data.
2Reliability
If distributed consistency checks are performed across striped volume sets, then consistency across volumes is improved, but verification time increases
Solution Approach 1:
The distributed consistency verification is segmented into independent units corresponding to individual inodes and their associated buffer trees. Each inode verification can be performed independently and stored in the verification cache, allowing parallel processing and reducing total verification time while maintaining consistency across the distributed striped volume set.
Solution Approach 2:
Distributed consistency checks are performed preliminarily across all volumes of the striped volume set before file system operations begin. By verifying all volume data in advance and caching the results, the system eliminates the need for time-consuming verification during actual file operations, reducing overall verification time while ensuring distributed consistency.
Data Source
AI summary
A system and method for performing a distributed consistency check of a clustered file system. File system functions for loading an inode and/or buffer tree are modified so that in response to either of these functions being invoked, a consistency check is performed. The consistency check verifies both local consistency on a node of the clustered file and a distributed check across the nodes of the storage system.