How is Live Migration achieved in vSphere?

Live Migration in vSphere is accomplished primarily through VMotion technology. VMotion enables the seamless transfer of running virtual machines (VMs) from one physical host to another without any service interruption. This process is critical for maintaining uptime and optimizing resource allocation in a virtualized environment.

When using VMotion, the state of the VM, including its memory and processing state, is copied to the destination host. This allows the VM to continue operating on the new host while still delivering services to users during the migration process. The technology leverages a combination of shared storage and network resources to ensure the migration is completed quickly and efficiently.

Each of the other options does refer to processes relevant to virtualization but does not perform live migration in the same way. For example, while DRS (Distributed Resource Scheduler) can automate resource distribution across hosts and can initiate migrations, it utilizes VMotion as the underlying technology to carry out those migrations. Manual reboot is a far less efficient method that leads to downtime, and storage migration refers to relocating VM storage, which does not equate to live migration of the entire VM itself. Therefore, VMotion stands out as the definitive means of achieving live migration within vSphere.