Redundant virtual machine placement for fault-tolerant consolidated server clusters

Consolidated server systems using server virtualization involves serious risks of host server failures that induce unexpected downs of all hosted virtual machines and applications. To protect applications requiring high-availability from unpredictable host server failures, redundant configuration using virtual machines can be an effective countermeasure. This paper presents a virtual machine placement method for establishing a redundant configuration against host server failures with less host servers. The proposed method estimates the requisite minimum number of virtual machines according to the performance requirements of application services and decides an optimum virtual machine placement so that minimum configurations survive at any k host server failures. The evaluation results clarify that the proposed method achieves requested fault-tolerance level with less number of hosting servers compared to the conventional N+M redundant configuration approach.