Impact of Live Migration on Multi-tier Application Performance in Clouds

Live migration technologies can contribute to efficient resource management in a cloud datacenter; however, they will inevitably entail downtime for the virtual machine involved. Even if the downtime is relatively short, its effect can be serious for applications sensitive to response time degradations. Therefore, cloud datacenter providers should control live migration operations to minimize the impact on the performance of applications running on the cloud infrastructure. With this understanding, we studied the impact of live migration on the performance of 2-tier web applications in an experimental setup using XenServer and RUBBoS benchmark. We revealed that the behavior of the transmission control protocol (TCP) can be the primary factor responsible for response time degradation during live migration. On the basis of the experimental results, we constructed functions to estimate the performance impact of live migration on the applications. We also examined a case study to demonstrate how cloud computing datacenters can determine the best live migration strategy to minimize application performance degradation.