Virtual machine migration FAQ: Live migration, P2V and more

Virtual machine migration offers many benefits, but it can be complicated. Luckily, several tools can help you migrate a virtual machine and address security concerns.

Virtual machine migration is one of the most important benefits of server virtualization technology.

The ability to migrate a virtual machine (VM) from one physical host to another can significantly boost an organization's disaster recovery efforts and improve business agility. It also comes in handy when an administrator needs to shut down a physical server for maintenance or upgrades because server downtime no longer equals application downtime.

The answers to these frequently asked questions on virtual machine migration offer tips on how to migrate a virtual machine, the benefits of live migration, security considerations and more. For more resources, check out this virtual server migration guide.

How can I migrate a virtual machine more quickly?

A virtual machine migration usually takes two to five hours, according to Enterprise Management Associates research. But if your goal is to migrate virtual machines more quickly, several tools are available. Live migration technologies from VMware, Microsoft and Citrix can migrate a virtual machine faster and with no downtime. Third-party vendor tools can automate the VM migration process. With these tools, you can reduce migration time to 30 minutes or less.

Speaking of live migration, what is it, exactly?

virtual machine live migration lets you migrate a virtual machine from one physical host to another without significantly interrupting application availability. Live migration captures a VM's complete memory state and the state of all its processor registers and sends that data to memory space on another server. That server then loads the processor registers, and the VM picks up right where it left off. All of major virtualization vendors offer live migration: VMware offers vMotion, Microsoft has Live Migration in Hyper-V, and Citrix Systems has XenMotion.

Are there security and compliance concerns around virtual machine migration?

If you don't follow these virtualization best practices around virtual machine migration, your infrastructure can be susceptible to security risks and even violate compliance regulations. Migrating a VM with customer credit card data to a host that also runs a public Web server, for example, violates the Payment Card Industry Data Security Standard. And without a proper change management system in place, VM migrations can even violate corporate policies. When you migrate a virtual machine, management software, provisioning software and integrated process management tools can help you address these security and compliance concerns.

What's a P2V migration?

P2V stands for "physical to virtual," so a P2V migration is the process of converting a physical server into a VM. To perform a physical-to-virtual machine migration, you must copy the physical server's bits to a virtual disk, install drivers and then modify the guest to support those drivers. In some cases -- but not always -- you can perform a P2V migration without shutting down the destination server.

What are my options for converting a physical machine to a virtual machine?

There are several ways to perform a physical-to-virtual machine migration and several conversion tools to make the process easier. Most tools fall into one of three categories: online tools, offline tools and image-based tools. VMware, Microsoft and Citrix all offer online tools, and several third-party vendors make offline and image-based tools. The right choice for you depends on your reasons for conversion, your acceptable level of downtime and the number of machines you want to migrate.

Next Steps

Virtual machine migration requires proper preparation

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