Abstract

So far virtual machine (VM) migration has focused on transferring the run-time memory state of the VMs in local-area networks (LAN). However, for wide-area network (WAN) migration it is crucial to not just transfer the VMs image but also transfer its local persistent state (e.g. file system), and its on-going network connections. In this paper we address both: by combining a block-level solution with pre-copying and write throttling we show that we can transfer an entire running web server (including its local persistent state) with minimal disruption (three seconds in the LAN and 68 seconds in the WAN ); by combining dynDNS with tunneling, existing connections can continue transparently while new ones are redirected to the new network location. Thus we show experimentally that by combining well-known techniques in a novel manner we can provide system support for migrating virtual execution environments in the wide area.