Topology-aware virtual machine replication for fault tolerance in cloud computing systems

Extensive use of cloud services has led to the need for service reliability for both the service provider as well as the users. In the Infrastructure as a Service cloud computing model, it is critical to ensure the reliability of resources such as virtual machines (VMs); storage networks etc. The paper proposes a replication-based fault tolerance method to improve the reliability of VM-based services. The proposed approach utilizes a data centre topology-aware method to select physical machines where replicas of VMs may be placed. The selection criteria for VM replica placement favour the physical machines at lower CPU temperature, more available space and at a lower edge length from the physical machine that primarily hosts the VM. By avoiding deteriorating physical machines, this policy increases the probability of successful recovery if the VM or its host physical machine fails. The proposed approach has been evaluated using two metrics, namely recoverability and the total bandwidth consumed in the replication and recovery process. The performance of the approach has been compared with a random replica placement method as well as a state of art algorithm. The simulation results illustrate that the proposed approach provides higher reliability than the other methods.