SnapMig: Accelerating VM Live Storage Migration by Leveraging the Existing VM Snapshots in the Cloud

Abstract

Virtual Machine (VM) live storage migration is becoming increasingly important and indispensable in the current cloud data centers, for the purposes of load balance, hardware maintenance and system upgrade. Nevertheless, conventional VM migration approaches induce significant extra storage and network traffic to the source server that is already heavily loaded or scheduled for upgrade or repair. As a result, both the VM performance perceived by the application/user and the migration performance are degraded significantly. In this paper, we aim to address this problem by proposing a novel scheme, called SnapMig , to improve the VM live storage migration efficiency and eliminate its performance impact on user applications at the source server by effectively leveraging the existing VM snapshots in backup servers. By outsourcing the task of transferring VM base image and snapshots to the destination server to backup servers, the source server only needs to migrate the latest state changes to the destination server, leading to simultaneous improvement on VM performance, migration time and multiple-VM migration efficiency. Our lightweight prototype implementation of the SnapMig scheme demonstrates that, compared with the state-of-the-art approaches, SnagMig can significantly reduce the migration time and improve the source-server VM performance at the same time. Moreover, the performance improvement provided by SnapMig becomes much more pronounced with multiple concurrent VM migrations.