The Best of Both Worlds with On-Demand Virtualization

Virtualization offers many benefits such as live migration, resource consolidation, and checkpointing. However, there are many cases where the overhead of virtualization is too high to justify for its merits. Most desktop and laptop PCs and many large web properties run natively because the benefits of virtualization are too small compared to the overhead. We propose a new middle ground: on-demand virtualization, in which systems run natively when they need native performance or features but can be converted on-the-fly to run virtually when necessary. This enables the user or system administrator to leverage the most useful features of virtualization, such as or checkpointing or consolidating workloads, during off-peak hours without paying the overhead during peak usage. We have developed a prototype of on-demand virtualization in Linux using the hibernate feature to transfer state between native execution and virtual execution, and find even networking applications can survive being virtualized.