Software Fault Tolerant System by using Virtualization Technology

The availability of the complex IT systemfor everything, everywhere, at all time is agrowing requirement. However, the availability ofIT infrastructures is still a massive challengecurrently. Unexpected downtime is mostly causedby software failure rather than hardware failure.Software failure can occur at the operating systemlevel and application level. Software aging wasobserved that once the software was started,potential fault conditions gradually accumulatedwith time leading to either performancedegradation or transient failures or both. Themost natural procedure to counteract suchsoftware aging is to apply the well-knowntechnique of software rejuvenation. In this paper,Software Fault Tolerant System is developed byapplying virtualization technology and SoftwareRejuvenation methodology. In order to improveavailability for IT systems, Active-standbyvirtualized clustering architecture is presentedand proactive software rejuvenation (VMSwitching) is applied. An availability Model isdeveloped using stochastic modelling andevaluated it through both numerical analysis andSHARPE (Symbolic Hierarchical AutomatedReliability and Performance Evaluator) toolsimulation. Web based Clinical InformationSystem is implemented on virtualized platform andperformance evaluation is carried out