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Partial Replication: Achieving Scalability in Redundant Arrays of Inexpensive Databases

2004; Springer Science+Business Media; Linguagem: Inglês

10.1007/978-3-540-27860-3_8

1611-3349

Emmanuel Cecchet, Julie Marguerite, Willy Zwaenepoel,

Advanced Data Storage Technologies

Clusters of workstations become more and more popular to power data server applications such as large scale Web sites or e-Commerce applications. There has been much research on scaling the front tiers (web servers and application servers) using clusters, but databases usually remain on large dedicated SMP machines. In this paper, we focus on the database tier using clusters of commodity hardware. Our approach consists of studying different replication strategies to achieve various degree of performance and fault tolerance. Redundant Array of Inexpensive Databases (RAIDb) is to databases what RAID is to disks. In this paper, we focus on RAIDb-1 that offers full replication and RAIDb-2 that introduces partial replication, in which the user can define the degree of replication of each database table. We present a Java implementation of RAIDb called Clustered JDBC or C-JDBC. C-JDBC achieves both database performance scalability and high availability at the middleware level without changing existing applications. We show, using the TPC-W benchmark, that partial replication (RAIDb-2) can offer better performance scalability (up to 25%) than full replication by allowing fine-grain control on replication. Distributing and restricting the replication of frequently written tables to a small set of backends reduces I/O usage and improves CPU utilization of each cluster node.