Everything You Always Wanted to Know about NFS Trace Analysis, but Were Afraid to Ask

Abstract

The past two decades in file system design have been driven by the sequence of trace-based file system studies that have informed the research community of the general access patterns applied to secondary storage systems. Those same two decades have witnessed a radical shift in the types of people who use computer systems and a resulting change in the workloads to which today’s systems are subjected. In this paper, we continue the tradition of trace-based studies, but with some important differences. First, we use passive monitoring of NFS traffic to collect our data; we believe that the non-invasive nature of this technique will improve the community’s ability to collect a wider range of workloads. Second, we focus on two different types of workloads, the traditional CS departmental load typically used in such studies and the load from a campus-wide, ISP-like environment. As might be expected, these workloads differ dramatically. The departmental workload does not follow previous predictions as directly as might have been expected and the ISP-like workload turns out to provide a detailed analysis of file-system-based mail handling. Our findings demonstrate that the set of static parameters and heuristics that most file systems provide is inadequate to adapt to complex, specialized workloads.