DATE: Thursday, April 7, 2005
TIME: 12:00 pm - 1:00 pm
PLACE: Wean Hall, Room 8220

Terrence Wong
Carnegie Mellon University

Comparison Based File Server Verification

Debugging servers is tough. When it comes to servers, "correct" behavior is difficult to define. The published specification may describe expected behavior in a vague manner, or not at all. Even worse, an implementation might have become so popular that it has introduced a de facto standard that does not conform to the original specification.

We propose a testing method which compares, for approximately the same client request, the response from a known working implementation called the reference server and the responses from a system under test (SUT) called the developmental server. Not only does this method allow for detecting differences between the servers' responses, it also allows for live client testing and performance comparisons.

Our prototype, called the Tee, implements comparison based file server verification for the NFS version 3 protocol. This talk will cover the design of our NFS Tee, the synchronization of objects between the two
servers, and the results that we have gotten.

This talk is based on joint work with Yuen-Lin Tan at VMWare, John Strunk, and Greg Ganger.

Terrence is a systems programmer at Carnegie Mellon University. He works in the Parallel Data Laboratory under the supervision of Greg Ganger and is interested in storage systems and NFS. Terrence received his BS in Computer Science from Carnegie Mellon University in 2004 and plans to pursue a graduate degree in the near future.

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