Pianola: A script-based I/O benchmark

Script-based I/O benchmarks record the I/O behavior of applications by using an instrumentation library to trace I/O events and their timing. A replay engine can then reproduce these events from the script in the absence of the original application. This type of benchmark reproduces real-world I/O workloads without the need to distribute, build, or run complex applications. However, faithfully recreating the I/O behavior of the original application requires careful design in both the instrumentation library and the replay engine. This paper presents the Pianola script-based benchmarking system, which includes an accurate and unobtrusive instrumentation system and a simple-to-use replay engine, along with some additional utility programs to manage the creation and replay of scripts. We show that for some sample applications, Pianola reproduces the qualitative features of the I/O behavior. Moreover, the overall replay time and the cumulative read and write times are usually within 10% of the values measured for the original applications.