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Reliability and availability are mandatory requirements for numerous applications. Technical apparatus to study system dependability is essential to support software deployment and maintenance. Software aging is a related issue in this context. Software aging is a cumulative process which leads systems with long-running execution to hangs or failures. Software rejuvenation is used to prevent software aging problems. Software rejuvenation actions comprise system reboot or application restart to bringing software to a stable fresh state. This paper proposes a methodology to conduct software aging and software rejuvenation experiments. The approach has three phases: (i) Stress Phase-stress environment with the accelerated workload to induce bugs activation; (ii) Wait Phase-stop workload submission to observe the system state after workload submission; (iii) Rejuvenation Phase-find the impacts caused by the software rejuvenation. We named our methodology as SWARE (Stress-Wait-Rejuvenation). To validate the SWARE methodology, we present a case study. This case study consists of an experiment of VM Live Migration as rejuvenation mechanism for VMM software aging. The considered testbed is a Private Cloud with OpenNebula and KVM 1.0. The obtained results show that VM live migration is useful as rejuvenation for VMM software aging.

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Abstract. Cloud service utilizes computing resources to store all of information on the Internet. It means that we can use the service anytime, in anywhere through a variety of IT equipment. For reliable operations of digital library cloud services, it is necessary to ensure dependability. In this paper, we apply the cold standby, hot standby, and load sharing in the system and compare our system with existing systems to measure the availability and reliability of dependability characteristic.