Evaluating the Performability of Systems with Background Jobs

As most computer systems are expected to remain operational 24 hours a day, 7 days a week, they must complete maintenance work while in operation. This work is in addition to the regular tasks of the system and its purpose is to improve system reliability and availability. Nonetheless, additional work in the system, although labeled as best effort or low priority, still affects the performance of foreground tasks, especially if background/foreground work is non-preemptive. In this paper, we propose an analytic model to evaluate the performance trade-offs of the amount of background work that a storage system can sustain. The proposed model results in a quasi-birth-death (QBD) process that is analytically tractable. Detailed experimentation using a variety of workloads shows that under dependent arrivals both foreground and background performance strongly depends on system load. In contrast, if arrivals of foreground jobs are independent, performance sensitivity to load is reduced. The...

• Type: Conference
• Year: 2006
• Where: DSN
• Authors: Qi Zhang, Ningfang Mi, Evgenia Smirni, Alma Riska, Erik Riedel
• Keywords: Computer Networks, DSN 2006, Foreground Jobs, Foreground Tasks, Performance