Availability and performance analysis of private cloud storage services

Abstract

Cloud computing is a set of new practices, technologies and concepts that favor communication services and data storage. Services like OneDrive, Google Drive and DropBox increase data availability and provide new features as synchronization and collaboration. These services require high availability and performance characteristics like high throughput, since it is fundamental to guarantee both business continuity and uninterrupted public services. In this research, we aim at evaluating availability and performance-related metrics for private cloud storage services. A hierarchical model-based strategy is proposed to evaluate availability throughput and system utilization by means of the composition of continuous-time Markov chains (CTMC), reliability block diagrams (RBD) and stochastic Petri nets (SPN). Case studies are presented to illustrate the applicability of the proposed models through a cloud storage service hosted in the Eucalyptus platform. We also adopt availability importance index to identify the most critical components in relation to the system availability. Based on such an index, we propose scenarios considering different degrees of redundancy and, accordingly, the effect on overall system availability and performance is explored. The results demonstrate that the proposed strategy can be an attractive approach for identifying which components should be supported with redundancy in order to increase the overall system performance and availability.