A Practical Evaluation in Openstack Live Migration of VMs Using 10Gb/s Interfaces

Live Migration (LM) of Virtual Machine (VM) is a process of transferring a working VM from on host to another host of a different physical machine without interfering the VM. In datacentre networks, LM enables flexibility in resource optimisation, fault tolerance and load balancing. However, in real time, the resource consumption and latency of live VM migration reduce these benefits to much less than their potential. In this paper, we present the results of an experimental study that evaluates LM in our unique high speed optical fibre network connecting Northern Ireland, Dublin and Halifax (Canada). We observe that using Pre-Copy LM extra large amounts of stressed memory leads to non convergence over high latency paths. However, using Post-copy LM the total migration time as well as downtime is dominated by specific memory utilisation patterns inside the virtualised guest. We experience variation in total migration time and downtime using Post-Copy LM considering Quality of Service (QoS) parameters, which can have significant impact in the cloud applications performance.