The Applications of Workload Characterization in The World of Massive Data Storage

Abstract

The digital world is expanding exponentially because of the growth of various applications in domains including scientific fields, enterprise environment and internet services. Importantly, these applications have drastically different storage requirements including parallel I/O performance and storage capacity. Various technologies have been developed in order to better satisfy different storage requirements. I/O middleware software, parallel file systems and storage arrays are developed to improve I/O performance by increasing I/O parallelism at different levels. New storage media and data recording technologies such as shingled magnetic recording (SMR) are also developed to increase the storage capacity. This work focuses on improving existing technologies and designing new schemes based on I/O workload characterizations in corresponding storage environments. The contributions of this work can be summarized into four pieces, two on improving parallel I/O performance and two on increasing storage capacity. First, we design a comprehensive parallel I/O workload characterization and generation framework (called PIONEER) which can be used to synthesize a particular parallel I/O workload with desired I/O characteristics or precisely emulate a High Performance Computing (HPC) application of interest. Second, we propose a non-intrusive I/O middleware (called IO-Engine) to automatically improve a given parallel I/O workload in Lustre which is a widely used HPC or parallel I/O system. IO-Engine can explore the correlations between different software layers in the deep I/O path, as well as workload patterns at runtime to transparently transform the workload patterns and tune related I/O parameters in the system. Third, we design several novel static address mapping schemes for shingled write disks (SWDs) to minimize the write amplification overhead in hard drives adopting SMR technology. Fourth, we propose a track-level shingled translation layer (T-STL) for SWDs with hybrid update strategy (in-place update plus out-of-place update). T-STL uses dynamic address mapping scheme and performs garbage collection operations by migrating selected disk tracks. This scheme can provider larger storage capacity and better overall performance with the same effective storage percentages when compared to the static address mapping schemes.