Scenarios for Hyper-V

Hyper-V was developed with a several key scenarios in mind. When Microsoft started developing Hyper-V, the development team spent a great deal of time meeting with customers who were using virtualization—small businesses, consultants who implement virtualization on behalf of their customers, and large companies with multimillion dollar IT budgets. The following key scenarios were developed as a result of those meetings; they represent customer needs, demands, and wants.


Server Consolidation
Systems are becoming increasingly powerful. A couple of years ago, it was rare to find a quadprocessor server at a price most customers could afford. Now, with major processor manufacturers providing multicore functionality, servers have more and more processing power. Multicore technology combines multiple processor cores onto a single die—enabling a single physical processor to run multiple threads of execution on separate cores. Virtualization and multicore technology work great together: If you’re combining multiple workloads onto a single server, you need to have as much processing power as possible. Multicore processors help provide the optimal platform for virtualization.

Businesses are increasingly likely to need multiple systems for a particular workload. Some workloads are incredibly complex, requiring multiple systems but not necessarily using all the power of the hardware. By taking advantage of virtualization, system administrators can provide a virtualized solution that better utilizes the host hardware—thus allowing administrators to get more out of their expenditure.

Workloads aren’t the only driving item behind virtualization. The power and cooling requirements of modern servers are also key driving factors. A fully loaded rack of servers can put out a significant amount of heat. (If you’ve ever stood behind one, you’re sure to agree—it’s a great place to warm up if you’ve been working in a cold server room.) All that heat has to come from somewhere. The rack requires significant power.

But for companies in high-rise buildings in the middle of major cities, getting additional power is incredibly difficult, if not impossible. In many cases, the buildings weren’t designed to have that much power coming in—and the companies can’t add more power without extensive retrofitting. By deploying virtualization, more workloads can be run on the same number of servers.


Testing and Development
For people working in a test or development role, virtualization is a key to being more productive. The ability to have a number of different virtual machines (VMs), each with its own operating system that’s ready to go at the click of a mouse, is a huge time-saver. Simply start up whichever VM has the operating system. You no longer need to install a clean operating system. Also, by using the snapshot functionality, users can quickly move between known states in the VM.

With Hyper-V’s rich Windows Management Interface (WMI) interfaces, testing can be started automatically. By scripting both Hyper-V and the operating system to be tested, testers can run a script that starts the VM, installs the latest build, and performs the necessary tests against it. A Hyper-V virtual machine is also portable. A tester can work in the VM; if an issue is found, the tester can save the state of the VM (including the memory contents and processor state) and transfer it to the developer, who can restore the state at their convenience. Because the state of the VM is saved, the developer sees exactly what the tester saw.


Business Continuity and Disaster Recovery
Business continuity is the ability to keep mission-critical infrastructure up and running. Hyper-V provides two important features that enable business continuity: live backup and quick migration. Live backup uses Microsoft Volume Shadow Services functionality to make a backup of the entire system without incurring any downtime, as well as provide a backup of the VM at a known good point in time. The system backup includes the state of all the running VMs. When a backup request comes from the host, Hyper-V is notified, and all the VMs running on that host are placed into a state where they can be backed up without affecting current activity; they can then be restored at a later time.

Quick migration is the ability to move a VM from one host to another in a cluster using Microsoft Failover Cluster functionality. During a quick migration, you save the state of the VM, move storage connectivity from the source host to the target host, and then restore the state of the VM. Windows Server 2008 added support for the virtual-machine resource type to the Failover Clustering tool, enabling you to make a VM highly available using functionality included with the operating system.

Disaster recovery is becoming a requirement for increasing numbers of businesses. With natural disasters such as Hurricane Katrina fresh in the minds of system administrators, enterprises are seeking ways to keep their businesses running throughout such events. You must consider more than just big disasters, though—small disasters or even simple configuration issues can lead to a mission-critical service being unavailable. Hyper-V includes support for geographically dispersed clusters (a new feature of Windows Server 2008).


Dynamic IT
Microsoft’s idea of a dynamic IT infrastructure involves self-managing dynamic systems— systems that adjust automatically to the workload they’re running. By using Hyper-V in conjunction with the systems-management functionality present in the System Center family of products, enterprises can take advantage of the benefits of virtualization to meet the demands of a rapidly changing environment. Now that we’ve covered Hyper-V’s key targeted scenarios, let’s review the architecture of Hyper-V to see how Microsoft has implemented support for them.

Source of Information : Sybex Windows Server 2008 Hyper-V Insiders Guide to Microsofts Hypervisor