Which type of migration allows live movement of a VM from one host to another without downtime?

The ability to move a virtual machine (VM) from one host to another without any downtime is a key feature of vMotion. This technology allows for the live migration of VMs, which means that the VM can continue to run and remain available to end users while the underlying resources it uses are being relocated.

During a vMotion operation, the memory and CPU state of the VM are copied from the source host to the destination host while the VM remains operational. Once the migration is complete, the VM is switched over to the destination host with minimal disruption, ensuring continuity of service. This capability is crucial in environments that require high availability and very little downtime for maintenance or load balancing activities.

Other types of migration, such as cold migration, involve shutting down the VM before moving it, which results in downtime. Cross-vCenter vMotion also allows for live migration between different vCenter Server instances but is a more specific use case. Batch migration refers to migrating multiple VMs together in a single task, which can also lead to downtime during the migration process for each VM involved. Thus, only vMotion is specifically designed for live migration without downtime.