Live migration of virtual machine based on full system trace and replay

Live migration of virtual machines (VM) across distinct physical hosts provides a significant new benefit for administrators of data centers and clusters. Previous migration schemes focused on transferring the runtime memory state of the VM. Those approaches employed memory pre-copy algorithm to synchronize the migrating VM states, which make VM live migration cost much network traffic and application downtime, especially for memory intensive workloads. This paper describes the design and implementation of a novel approach CR/TR-Motion that adopts checkpointing/recovery and trace/replay technology to provide fast, transparent VM migration. With execution trace logged on the source host, a synchronization algorithm is performed to orchestrate the running source and target VM until they get a consistent state. We also give a formalized characterization about the migration evaluation metrics and make a mathematical analysis about our algorithm. Our scheme can greatly reduce the migration downtime and network bandwidth consumption. Experimental measurements show that our approach can drastically reduce migration overheads compared with pre-copy algorithm: up to 72.4% on application observed downtime, up to 31.5% on total migration time and up to 95.9% on the data to synchronize the VM state, while the application performance overhead due to migration is less than 8.54% on average.