Abstract:
The availability of the complex IT system
for everything, everywhere, at all time is a
growing requirement. However, the availability of
IT infrastructures is still a massive challenge
currently. Unexpected downtime is mostly caused
by software failure rather than hardware failure.
Software failure can occur at the operating system
level and application level. Software aging was
observed that once the software was started,
potential fault conditions gradually accumulated
with time leading to either performance
degradation or transient failures or both. The
most natural procedure to counteract such
software aging is to apply the well-known
technique of software rejuvenation. In this paper,
Software Fault Tolerant System is developed by
applying virtualization technology and Software
Rejuvenation methodology. In order to improve
availability for IT systems, Active-standby
virtualized clustering architecture is presented
and proactive software rejuvenation (VM
Switching) is applied. An availability Model is
developed using stochastic modelling and
evaluated it through both numerical analysis and
SHARPE (Symbolic Hierarchical Automated
Reliability and Performance Evaluator) tool
simulation. Web based Clinical Information
System is implemented on virtualized platform and
performance evaluation is carried out.
