A study on server Sleep state transition to reduce power consumption in a virtualized server cluster environment

Growth of Cloud computing has fueled the demand for large infrastructures called data centers. While the objective of the cloud computing ecosystem is to move computation and processing away towards a centralized environment, the fallout lies in the power and energy consumption of these infrastructures. Reducing power consumption is an essential requirement for Cloud resource providers to decrease operating costs. One of the options to reduce power consumption is to reduce the number of servers in IDLE (unused) state - as these IDLE servers consume as much as 60% of peak power. Number of servers in IDLE state can be reduced by turning off IDLE servers or transitioning these IDLE servers to low power SLEEP state. With virtualization being the backbone to provision cloud computing services, we use simulation to study and report the impact of using SLEEP state on the server with its virtual machines (VM) servicing application workload requests. We look at two parameters: a) power consumption of the cloud computing environment, b) average response time per request. Our simulation results show that using SLEEP state at server level, and the server with its VMs' servicing application workload requests, we can achieve a 2% savings in average power usage and around 27% savings in average response time per request.