C. Zhang, X. Yu, A. Krishnamurthy, and R. Y. Wang.
Configuring and Scheduling an Eager-Writing Disk Array for
a Transaction Processing Workload.
Proc. First Conference on File and Storage
Technologies. January 2002.
Transaction processing applications such
as those exemplified by the TPC-C benchmark are among the most
demanding I/O applications for conventional storage systems. Two
complementary techniques exist to improve the performance of these
systems. Eager-writing allows the free block that is closest to
a disk head to be selected for servicing a write request, and
mirroring allows the replica that is closest to be
selected for servicing a read request. Applied individually, the
effectiveness of each of these techniques is limited. An
eager-writing disk array (EW-Array) combines these two complementary
techniques. In such a system, eager-writing enables low-cost replica
propagation so that the system can provide excellent performance for
both read and write operations while maintaining a high degree of
reliability. To fully realize the potential of an EW-Array, we must
answer at least two key questions. First, since both eager-writing
and mirroring rely on extra capacity to deliver performance
improvements, how do we satisfy competing resource demands given a
fixed amount of total disk space? Second, since eager-writing
allows data to be dynamically located, how do we exploit this high degree
of location independence in an intelligent disk scheduler?
In this paper, we address these two key
questions and compare the resulting EW-Array prototype performance
against that of conventional approaches. The experimental results
demonstrate that the eager-writing disk array is an effective approach
to providing scalable performance for an important class
of transaction processing applications.