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ABSTRACTReplication Policies for Layered Clustering of NFS Servers Raja R. Sambasivan, Andrew J. Klosterman, Gregory R. Ganger Electrical and Computer Engineering Layered clustering offers cluster-like load balancing for unmodified NFS or CIFS servers. Read requests sent to a busy server can be offloaded to other servers holding replicas of the accessed files. This paper explores a key design question for this approach: which files should be replicated? We find that the popular policy of replicating readonly files offers little benefit. A policy that replicates readonly portions of read-mostly files, however, implicitly coordinates with client cache invalidations and thereby allows almost all read operations to be offloaded. In a read-heavy trace, 75% of all operations and 52% of all data transfers can be offloaded. FULL PAPER: pdf |