Zero-copy Migration for Lightweight Software Rejuvenation of Virtualized Systems

Abstract

Virtualized systems tend to suffer from software aging, which is the phenomenon that the state of a running system degrades with time. Software aging is restored by a technique called software rejuvenation, e.g., a system reboot. To reduce the downtime due to software rejuvenation, all the virtual machines (VMs) on an aged virtualized system have to be migrated in advance. However, VM migration stresses the system and causes performance degradation. In this paper, we propose VMBeam, which enables lightweight software rejuvenation of virtualized systems using zero-copy migration. When rejuvenating an aged virtualized system, VMBeam starts a new virtualized system at the same host by using nested virtualization. Then it migrates all the VMs from the aged virtualized system to the clean one. At this time, VMBeam directly relocates the memory of the VMs on the aged virtualized system to the clean virtualized system without any copy. We have implemented VMBeam in Xen and confirmed the decreases of system loads.