Abstract: Enabled by virtualization technologies, various multi-tier applications are hosted by virtual machines (VMs) in cloud data centers. Live migration of multi-tier applications across geographically distributed data centers is important for load management, power saving, routine server maintenance and quality-of-service. Different from a single-VM migration, VMs in a multi-tier application are closely correlated, which results in a correlated VM migrations problem. In this paper, we explore performance of multi-tier applications during the virtual machine migration in cloud as well as issues and solutions during VMs migration.

Keywords: Cloud, live migration, multi-tier application, virtual machine.