Virtual server migration guide: An introduction
If you're an IT manager or administrator who wants to get a grasp on how virtual server migrations work, this section is for you. In it, we outline the various kinds of virtual server migration and the purpose for each. We also explain the difference between manual physical-to-virtual (P2V), semi-automated, and automated P2V migration.
One of the key factors that has driven server virtualization adoption is the ability to move workloads from one physical server to another. By enabling IT managers or virtualization administrators to use virtual server migrations to shift server resources as needed, IT shops can reap key benefits of server virtualization, such as minimizing system downtime, enabling disaster recovery and business continuity, and increasing IT flexibility and agility. In short, virtual server migration provides the keys to the kingdom for IT managers struggling to manage their IT environment. And these benefits compound as a virtualized infrastructure grows.
But IT managers and admins can fall prey to the misconception that virtual machine (VM) migration involves just a few clicks of the mouse. Instead, virtual server migrations can be far more complicated and, without careful planning and an understanding of your existing infrastructure, introduce new problems.
This guide to virtual server migrations helps you avoid migration problems by explaining how virtual server migrations work, examining best practices for virtual server migration, outlining how various server migration tools aid VMware and Microsoft Hyper-V virtualization environments, and explaining how to troubleshoot failed conversions .
Defining virtual server migrations
Virtual server migrations come in a few flavors. You can convert physical servers to virtual servers, virtual servers to virtual servers, or virtual servers to physical ones. These forms of virtual server migration should not be confused with live migration, a process that enables you to move virtual machines from one host to another without creating downtime for users; VMware calls its live migration feature VMotion and Microsoft calls its feature Live Migration (formerly Quick Migration).
During a physical-to-virtual (P2V) migration, the process decouples and migrates a physical server's resources -- its operating system, applications, and data -- to a virtual machine (VM) guest hosted on a virtualized platform. In short, when you do a P2V migration, you create a VM.
Migrations aren't just one way, either. You can also conduct virtual-to-physical (V2P) migrations, particularly to troubleshoot a problem on a virtual machine. By converting a VM back to a physical server, you can identify whether the problem originates from the virtualization layer. You can also perform virtual-to-virtual (V2V) server migrations and migrate a virtual server's resources to another virtual machine. V2V can be used to copy or restore files, programs or OS components to one virtual machine to another. V2V migration can also be used with P2V and V2P migration to copy the OS and applications from a computer's hard disk to a virtual machine and from there to an unlimited number of other virtual machines or computers.