Performance and availability modeling of hybrid storage systems

The need for performance has motivated the increasing adoption of solid-state drives (SSD) both in personal computers and data centers. However, the high cost per gigabyte and reduced lifetime hinder the thorough replacement of hard disk drives (HDD) with SSDs. To mitigate these issues, several architectures have been conceived based on hybrid storage systems, but performance and dependability models have not been proposed to better assess such different architectures. This paper presents an approach based on stochastic models for performance and availability modeling of hybrid storage systems, using stochastic Petri nets (SPN) and reliability block diagrams (RBD). A case study based on OpenStack Swift platform is adopted to demonstrate the feasibility of the proposed approach.