This paper tackles performability modelling and analysis of versatile server virtualised systems subject to workload-dependent software aging, failures and rejuvenation. We develop a modular modelling approach based on stochastic reward nets to investigate dependencies between several server virtualised system modules including virtual machine monitor, virtual machine, data intensive applications and workload-aware power management mechanism. Two case studies are considered, each of them accounts for a specific virtual machine monitor rejuvenation technique (Cold-VM or Migrate-VM). We show through numerical analysis how steady-state availability and power-performance metric are impacted by workload-dependent software aging and workload burstiness.