Inter-rack live migration of multiple virtual machines

Within datacenters, often multiple virtual machines (VMs) need to be live migrated simultaneously for various reasons such as maintenance, power savings, and load balancing. Such mass simultaneous live migration of multiple VMs can trigger large data transfers across the core network links and switches, and negatively affect the cluster-wide performance of network-bound applications. In this paper, we present a distributed system for inter-rack live migration (IRLM), i.e., parallel live migration of multiple VMs across racks. The key performance objective of IRLM is to reduce the traffic load on the core network links during mass VM migration through distributed deduplication of VMs' memory images. We present an initial prototype of IRLM that migrates multiple QEMU/KVM VMs within a Gigabit Ethernet cluster with 10GigE core links. We also present preliminary evaluation on a small testbed having 6 hosts per rack and 4 VMs per host. Our evaluations show that, compared to the default live migration technique in QEMU/KVM, IRLM reduces the network traffic on core links by up to 44% and the total migration time by up to 26%. We also demonstrate that network-bound applications experience a smaller degradation during migration using IRLM.