The 35th annual conference on Astronomical Data Analysis Software & Systems 2025 in Görlitz, Germany

With astronomy entering an era of petabyte to exabyte scale data from next-generation telescopes and surveys, existing cloud platforms face critical data management challenges. Traditional approaches of mounting entire datasets or copying filtered subsets create trade-offs between access efficiency and storage costs, while conventional storage engines lack flexible permission control. To address this, this paper presents a POSIX-compliant read-only file system designed for non-landing data scenarios. The system integrates FUSE for POSIX interface implementation, libnfs for server-side data retrieval, and a database-driven metadata layer that enables file-level access isolation through SQL-defined policies. Performance testing indicates that maintaining under 5,000 files per directory ensures optimal user experience, while read operations achieve speeds of more than 50MB/s under a gigabit local area network – sufficient for most application scenarios in astronomical data workflows. Our results indicate that YourFS effectively balances accessibility and cost-efficiency for massive datasets, providing a viable paradigm for server-side data management in cloud platforms.