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Computer Science Colloquia

Wednesday, May 1, 2013
Ashwin Raghav Mohan Ganesh
Advisor: Andrew Grimshaw
Attending Faculty: Jack Stankovic (Chair), Kamin Whitehouse, and Marty Humphrey

10:00 AM, Rice Hall, Rm. 242

PhD Qualifying Exam Presentation
A Scalable Application-level Distributed Filesystem Notifications Solution


Filesystem event notifications help applications track file events. Although most operating systems are provisioned to notify applications of events on local file objects, there exists no scalable solution to track events on files that reside on distributed filesystems. In this paper, we introduce Rnotify, a scalable application level solution to this problem.

Our system has four key properties. Firstly, the Rnotify API provides application semantics nearly equivalent to the existing Linux notifications API (Inotify). Linux applications can potentially use Rnotify with minimal code changes. Secondly, by slightly modifying the semantics of Inotify, Rnotify will dispatch event notifications under a latency of 10 milliseconds for 85% of useful filesystem changes without being subject to event queue overflows. Thirdly, applications that choose to use Rnotify as a High throughput notification delivery system can do so at low latency costs by distributing their notification processing. Lastly, a clear decomposition of functionalities between different components of Rnotify ensures that the system can accommodate different workloads imposed by traditional HPC or modern Web Applications by scaling specific components. We support our claims by testing Rnotify with a GlusterFS deployment on an Amazon Web Services High Performance Computing Cluster.