A lightweight software fault-tolerance system in the cloud environment

With the development of cloud computing, the demand of high availability for services is growing. Unfortunately, software failures greatly reduce system availability. This paper presents a lightweight software fault-tolerance system, called SHelp, which can effectively recover programs from many types of software bugs in the cloud environment. With error virtualization techniques, it proposes weighted' rescue points techniques to effectively survive software failures through bypassing the faulty path. For multiple application instances running on different virtual machine, a three-level storage hierarchy with several comprehensive cache updating algorithms for rescue points management is adopted to share error handling information. On the one hand, SHelp can reduce the redundancy for multiple application instances; on the other hand, it can more effectively and quickly recover from faults caused by the same bugs. A Linux prototype is implemented on an open-source virtual machine monitor platform, Xen, and evaluated using four Web server applications that contain various types of bugs. The experimental results show that SHelp can recover server applications from these bugs in just a few seconds with modest performance overhead. Copyright (c) 2013 John Wiley & Sons, Ltd.