Speaker
Description
With the continuous advancement of HEP detectors and online reconstruction capabilities, the scale of experimental data is growing rapidly. The data pattern is increasingly characterized by "massive small files distributed across multiple data centers." On one hand, the surge in small files creates bottlenecks in metadata and directory operations; on the other hand, cross-data center access often relies on complex cross-domain operational strategies, making it difficult to balance performance with scalability.
To address these issues, this paper proposes JWanFS, a distributed file system designed for HEP experiments. It provides a unified namespace and nearest-access capabilities for multi-site users, with optimizations specifically for Wide Area Network (WAN) environments.
The key designs of JWanFS include:
- Storage & Interface Optimization: Enhances small file organization and access strategies based on SeaweedFS, and supports multi-protocol access (NFS, S3, XRootD) via a gateway layer to seamlessly integrate with data analysis and AI training workflows.
- Metadata Synchronization: Utilizes MongoDB's asynchronous replication (Oplog) mechanism for efficient cross-site metadata distribution and minimizes directory traversal overhead through range query optimization.
- Access Acceleration: Combines a "nearest data center" policy with client-side multi-level caching to significantly reduce WAN Round-Trip Time (RTT) and cross-domain jitter.
JWanFS demonstrates stable and efficient throughput and scalability under typical small-file workloads and cross-domain access scenarios. We plan to deploy and iterate the system in further HEP experiments (such as LHAASO and JUNO) to provide reliable and efficient cross-domain storage infrastructure support for the next generation of high energy physics experiments.