Conversations about server migration are nothing new to the virtual administrator. Migrating a virtual machine from one physical host to another is often one of the earliest tasks performed in a new virtualized server environment. Even after the initial virtualization project completes migration of physical servers to virtual (P2V) to convert a physical machine to a virtual machine is relatively commonplace. In fact many organizations leverage P2V products like Vizioncore’s vConverter to move their physical machines to the virtual environment solely to take advantage of virtualized disaster recovery. In this use case, the physical systems are converted into VMs but the applications continue to run day-to-day on the physical server. The VM is only there in case the physical system fails. Virtualized disaster recovery is often considered easier to manage than other DR solutions because millions of files are encapsulated into a single server image. Also since multiple virtual machines can reside on a single server there is a reduction in physical hardware requirements at the disaster recovery or facility.

The challenge with the virtual disaster recovery approach is moving a virtual machine out of the virtual environment after a server or data center failure. In many cases, especially in a prolonged recovery effort, there is a desire to move the application back to a stand alone physical server. This allows the DR server to resume its original state. The challenge is that until recently the conversion of virtual systems was a ‘one-way street’.

The move from a virtual machine to a physical machine is not limited to the extreme case of a disaster. It may also be helpful in a situation where there’s a support problem and one of the variables to be eliminated is running the application in the virtual environment. One of the challenges here is the movement of a virtual system that may have never been stand alone to a physical server.

What’s required then is for migration tools to become migration applications, like Vizioncore did when it released vConverter 5.0. A migration application allows for a physical machine to move to virtual and then back to physical. This includes systems that were virtual from the beginning.

The ability to move from physical to virtual and virtual to physical brings added flexibility to the virtual administrator beyond these disaster and support use cases. It also brings a new ability to handle unexpected peaks in resource requirements. For example, a stand alone server can be set up for the sole purpose of receiving what were formerly VMs to support an increase in performance needs. This is a cost effective use of physical hardware, since only one or two extra systems need to be installed for this purpose and used almost as ‘global spares’. When such a performance peak occurs the VM can be migrated to the physical host until the peak subsides, at which point it can be migrated back. This gives the VM unfettered access to a stand alone system without the overhead of other VMs or the virtualization hypervisor itself.

A migration application with the ability to migrate the complete cycle, P2V2P, enables physical systems to participate fully in a virtual disaster recovery strategy as well. The physical machine can be converted to a virtual machine on a regular basis, which some utilities can do incrementally, meaning that the entire physical system does not need to be converted each time, merely updated. Then, once in the virtual environment, the VM of the physical system stays in a powered-off state until there is either a failure of the physical server or the data center. When one of those events occurs the VM can be powered on and operations restored, possibly at a constrained rate, while a new physical server is being implemented. Once the new system is in place the VM can be converted back to the new physical server and operations can return to normal.

VM conversion as an application mitigates the risk associated with the testing of new virtual infrastructures, most notably Microsoft's Hyper-V. Many organizations are evaluating Hyper-V and trying to decide on when to use it vs. other hypervisors like VMware's vSphere. There are bound to be applications that run just as well in both environments, and one may be more economical. VM conversion as an application allows the virtual administrator to move from one virtual environment to another; in case it’s determined that another hypervisor is more suited to the application.

Planning for the future is difficult in the virtual environment and knowing how applications will continue to perform in the future is hard to predict. VM conversion as an application provides the virtual administrator with the flexibility of never being boxed in. They can move from one virtual environment to another, and then if need be, to a stand alone physical system.

Driving out cost in a virtual environment involves running resources closer to their maximum operational levels. However, removing that headroom can create a greater risk of running out. Virtual-to-physical machine migration allows the administrator to be protected from those risks by having a ‘standby server’ available to take some of that load in case resources become too constrained. It should also lead to complete confidence in further optimizing the virtual environment.

Vizioncore is a client of Storage Switzerland

George Crump, Senior Analyst