A method for transferring one or more guest operating system (OS) using a remote server. The remote server periodically obtains a central processing unit (CPU) utilization ratio of each guest OS installed in each cloud server of the data center. The remote server counts the number of times of obtaining the CPU utilization ratio, and calculates a predicted average of the CPU utilization ratio for each cloud server if the counted number of the times is equal to a predetermined number. The remote server transfers one or more guest OS from the cloud server to other cloud servers before a predetermined time, in response to a determination that the predicted average of the CPU utilization ratio of the cloud server is greater than a predetermined average.