FSMonitor: Scalable File System Monitoring for Arbitrary Storage Systems

Data automation, monitoring, and management tools are reliant on being able to detect, report, and respond to file system events. Various data event reporting tools exist for specific operating systems and storage devices, such as inotify for Linux, kqueue for BSD, and FSEvents for macOS. However, these tools are not designed to monitor distributed file systems. Indeed, many cannot scale to monitor many thousands of directories, or simply cannot be applied to distributed file systems. Moreover, each tool implements a custom API and event representation, making the development of generalized and portable event-based applications challenging. As file systems grow in size and become increasingly diverse, there is a need for scalable monitoring solutions that can be applied to a wide range of both distributed and local systems. We present here a generic and scalable file system monitor and event reporting tool, FSMonitor, that provides a file-system-independent event representation and event capture interface. FSMonitor uses a modular Data Storage Interface (DSI) architecture to enable the selection and application of appropriate event monitoring tools to detect and report events from a target file system, and implements efficient and fault-tolerant mechanisms that can detect and report events even on large file systems. We describe and evaluate DSIs for common UNIX, macOS, and Windows storage systems, and for the Lustre distributed file system. Our experiments on a 897 TB Lustre file system show that FSMonitor can capture and process almost 38 000 events per second.