What is the least amount of downtime migration method for VMs when moving to a new Hyper-V host?

The least amount of downtime during the migration of virtual machines (VMs) to a new Hyper-V host is achieved through live migration. This method allows VMs to be moved while they are still running, meaning that users can continue to access applications and services without interruption.

Live migration works by transferring the memory state and the workload of the VM over the network from the source host to the destination host while the VM is still operational. The process involves transferring the memory pages that have changed since the last transfer to ensure minimal disruption. When the migration is nearing completion, the VM briefly freezes to ensure a final synchronization of all memory states, but this downtime is typically seconds or even less, which is significantly lower than other migration methods.

In contrast, snapshot migration involves creating a snapshot of the current state of the VM, which may require downtime as the state is saved. Offline migration requires stopping the VM entirely, resulting in significant downtime since the VM cannot be accessed during the process. Backup and restore methods also involve significant downtime due to the necessity of shutting down the VM to create a backup and then restoring it on the new host.

Because live migration allows for seamless transfer with minimal service interruption, it stands out as the most suitable option for scenarios where uptime is