This document discusses and compares offline and live virtual machine migration techniques. Offline migration involves suspending a VM, copying its memory image to the destination, and resuming it there, while live migration copies memory pages iteratively during operation to achieve seamless migration with minimal downtime. The paper aims to analyze the total migration time, downtime, and impact on application performance of offline versus live migration. It reviews related work on improving live migration and discusses the pre-copy live migration approach in detail.