What is the term used to describe moving a virtual machine from one host to another when the power is off?

Virtualization is the process of creating a software-based, or "virtual" version of a computer, with dedicated amounts of CPU, memory, and storage that are "borrowed" from a physical host computer—such as your personal computer— and/or a remote server—such as a server in a cloud provider's datacenter. A virtual machine is a computer file, typically called an image, that behaves like an actual computer. It can run in a window as a separate computing environment, often to run a different operating system—or even to function as the user's entire computer experience—as is common on many people's work computers. The virtual machine is partitioned from the rest of the system, meaning that the software inside a VM can't interfere with the host computer's primary operating system.

Here are a few ways virtual machines are used:

Building and deploying apps to the cloud.
Trying out a new operating system (OS), including beta releases.
Spinning up a new environment to make it simpler and quicker for developers to run dev-test scenarios.
Backing up your existing OS.
Accessing virus-infected data or running an old application by installing an older OS.
Running software or apps on operating systems that they weren't originally intended for.

While virtual machines run like individual computers with individual operating systems and applications, they have the advantage of remaining completely independent of one another and the physical host machine. A piece of software called a hypervisor, or virtual machine manager, lets you run different operating systems on different virtual machines at the same time. This makes it possible to run Linux VMs, for example, on a Windows OS, or to run an earlier version of Windows on more current Windows OS.

And, because VMs are independent of each other, they're also extremely portable. You can move a VM on a hypervisor to another hypervisor on a completely different machine almost instantaneously.

Because of their flexibility and portability, virtual machines provide many benefits, such as:

Cost savings—running multiple virtual environments from one piece of infrastructure means that you can drastically reduce your physical infrastructure footprint. This boosts your bottom line—decreasing the need to maintain nearly as many servers and saving on maintenance costs and electricity.
Agility and speed—Spinning up a VM is relatively easy and quick and is much simpler than provisioning an entire new environment for your developers. Virtualization makes the process of running dev-test scenarios a lot quicker.
Lowered downtime—VMs are so portable and easy to move from one hypervisor to another on a different machine—this means that they are a great solution for backup, in the event the host goes down unexpectedly.
Scalability—VMs allow you to more easily scale your apps by adding more physical or virtual servers to distribute the workload across multiple VMs. As a result you can increase the availability and performance of your apps.
Security benefits— Because virtual machines run in multiple operating systems, using a guest operating system on a VM allows you to run apps of questionable security and protects your host operating system. VMs also allow for better security forensics, and are often used to safely study computer viruses, isolating the viruses to avoid risking their host computer.

You can move a non-running virtual machine from one repository to another. During the move you can specify where the disks should be moved to using a clone customizer. If you keep the clone customizers to the default settings (the same as the original virtual machine), a move is essentially the same as migrating the virtual machine to another Oracle VM Server. You can change the location of disks and the virtual machine configuration file to another storage repository when you move a virtual machine using a clone customizer.

Note

The network information is not changed when moving a virtual machine, so you cannot move VNICs between networks. Any network changes you make in a clone customizer are ignored when moving a virtual machine. This allows you to preserve the virtual machine in its original state, while moving the configuration file and storage to a different repository.

Migrating Virtual Machines Between Oracle VM Servers

Migrating a virtual machine is a process to move a virtual machine from one Oracle VM Server, or server pool, to another. If the virtual machine is running during the migration, the applications continue to run, uninterrupted and this is called live migration. This feature is important, and useful, when the existing Oracle VM Server may be out of commission (if HA is enabled), or on a planned shutdown for maintenance purposes. Live migration can only be performed within the same server pool, so a running virtual machine cannot be moved out of its server pool. Live migration does not require HA to be enabled; it can occur in a server pool simply by selecting a running virtual machine and migrating it, independently of whether or not the server pool is clustered and/or whether the virtual machine has its HA flag set.

You can migrate one or more virtual machines at a time. When migrating multiple virtual machines, the migrations are performed serially and not concurrently, so one migration is performed, then the next, until all the migrations are completed. Cross-server pool migration is allowed, though the virtual machines must first be stopped. A virtual machine must also be in a stopped state before migrating it off of any server (an Unassigned Virtual Machine). When you migrate a virtual machine to another server pool, the virtual machine is not deployed to a particular Oracle VM Server until you start the virtual machine, then the placement strategies for the virtual machine depends on the Oracle VM Server roles, and destination server pool policies such as Distributed Resource Scheduler (DRS) and Distributed Power Management (DPM). See Section 6.2, “What are Server Roles?” for information on Oracle VM Server roles, and Section 6.11, “What are Server Pool Policies?” for information on server pool policies.

If you have set the inbound migration lock feature to disallow new virtual machines on an Oracle VM Server, then any automatic migration policies you set are restricted from migrating virtual machines, or creating new ones on that server. See Section 7.11, “How Can I Protect Virtual Machines?” for more information on using the inbound migration lock feature.

The CPU family and model number of the source and destination computers must be compatible in order to perform live migration. This means, for instance, that you cannot migrate a virtual machine from an x86-based server pool to a SPARC-based server pool, or vice versa. Equally, you cannot perform a live-migration within the same x86-server pool, if the servers have different CPU families or model numbers. For more information on CPU compatibility, please see Section 6.13, “What are Server Processor Compatibility Groups?”.

You can use cold migration to move a virtual machine and its associated disks from one datastore to another. The virtual machines are not required to be on shared storage.

Make sure that you are familiar with the requirements for cold migration. See Cold Migration.
Required privilege:

Power off or suspend the virtual machine.
Right-click the virtual machine and select Migrate.

Select the migration type and click Next.

Option	Description
Change compute resource only	Move the virtual machine to another host.
Change storage only	Move the virtual machine’s configuration file and virtual disks.
Change both compute resource and storage	Move the virtual machine to another host and move its configuration file and virtual disks.

If you change the compute resource of the virtual machine, select the destination compute resource for this virtual machine migration and click Next.
If you change the storage of the virtual machine, enter the required details in the Select Storage page.

If you change the compute resource of the virtual machine, select destination networks for the virtual machine migration.

Option	Action
Select a destination network for all VM network adapters connected to a valid source network.	Click the arrow in the Destination Network column and select Browse. Select a destination network and click OK. Click Next.
Select a new destination network for each VM network adapter connected to a valid source network.	Click Advanced. Click the arrow in the Destination Network column and select Browse. Select a destination network and click OK. Click Next.

On the Ready to complete page, review the details and click Finish.

vCenter Server moves the virtual machine to the new host or storage location.

Event messages appear in the Events tab. The data displayed on the Summary tab shows the status and state throughout the migration. If errors occur during migration, the virtual machines revert to their original states and locations.