A comparative experimental study of software rejuvenation overhead

In this paper we present a comparative experimental study of the main software rejuvenation techniques developed so far to mitigate the software aging effects. We consider six different rejuvenation techniques with different levels of granularity: (i) physical node reboot, (ii) virtual machine reboot, (iii) OS reboot, (iv) fast OS reboot, (v) standalone application restart, and (vi) application rejuvenation by a hot standby server. We conduct a set of experiments injecting memory leaks at the application level. We evaluate the performance overhead introduced by software rejuvenation in terms of throughput loss, failed requests, slow requests, and memory fragmentation overhead. We also analyze the selected rejuvenation techniques' efficiency in mitigating the aging effects. Due to the growing adoption of virtualization technology, we also analyze the overhead of the rejuvenation techniques in virtualized environments. The results show that the performance overheads introduced by the rejuvenation techniques are related to the granularity level. We also capture different levels of memory fragmentation overhead induced by the virtualization demonstrating some drawbacks of using virtualization in comparison with non-virtualized rejuvenation approaches. Finally, based on these research findings we present comprehensive guidelines to support decision making during the design of rejuvenation scheduling algorithms, as well as in selecting the appropriate rejuvenation mechanism. (c) 2012 Elsevier B.V. All rights reserved.