Analysis of self-similarity in I/O workload using structural modeling

Abstract

Demonstrates that disk-level I/O requests are self-similar in nature. We show evidence (both visual and mathematical) that I/O accesses are consistent with self-similarity. For this analysis, we have used two sets of disk activity traces collected from various systems over different periods of time. In addition to studying the aggregated I/O workload that is directed to the storage system, we perform a structural modeling of the workload in order to understand the underlying causes that produce the observed self-similarity. This structural modeling shows that self-similar behavior can be explained by combining two different approaches: the on/off source model and Cox's model. The former applies to those processes that remain active during the whole trace, while the latter applies to sources that show a very short activity time.