Companies once prided themselves on having a huge data center full of servers, storage devices and network hubs, all working together to run the business. You need a huge amount of infrastructure just to support your computing infrastructure. One mammoth search engine company owns a data center that is so complex that it even creates its own climate within the building.
Data Center Virtualization is about separating hardware, software and networks so they no longer have to physically co-exist. It’s also about combining functionality and sharing resources to reduce the amount of hardware needed. This leads to less license fees, less maintenance and less overall infrastructure overhead.
Virtualization of data center functionality can happen at various levels of the architecture. The result could be a completely virtual architecture or one that combines virtual and dedicated functions.
Virtualization of Operating Systems
Instead of a machine dedicated to one particular operating system (OS), virtual machine managers (VMMs) can control multiple OS running on one machine. Each OS runs as if it was the only one on that machine. Users log into their computer as usual and the VMMs direct their request to the appropriate OS. The multiple OS instances don’t communicate with each other so there’s no fear that a Windows 8 user will get a response from the Redhat Linux OS. Less dedicated machines are needed in this environment.
Virtualization of Application Servers
This is the earliest form of virtualization. It is also referred to as load balancing. Multiple servers running the same application software receive requests from one or more front-end servers. The end-user request comes into the front-end server and sends it to be processed by one of the multiple back-end servers based on the load-balancing rules established by the system administrator. While this implies using more machines as application servers, they can be lower end devices. In a typical growth environment, getting bigger and doing more meant purchasing larger servers. Using virtual application servers means purchasing one or more additional low end devices to increase capacity.
Virtualization of Applications
This is basically the environment where applications do not reside on a user’s machine. They could be located in a cloud, onsite or off, or on a local application server. The user runs their applications as usual on their computer but the actual executables and libraries are on other devices. This is the old “thin client” model updated for the cloud. This saves a company on maintenance, upgrades, licenses and allows them to better control access to the applications.
Virtualization of Networks
Using all of the above virtualization concepts, networks can also be architected away from single function, single purpose hardware and software into resources that serve multiple requests and devices. The network bandwidth is divided up into pieces that are allocated and re-allocated on demand to make the best use of the bandwidth. Instead of having dedicated network bandwidth to a specialty printer that is rarely used, the virtual network will create a connection when needed and release the bandwidth when the request is completed.
Virtualization of Storage
Network Attached Storage (NAS) and Storage Area Network (SAN) technologies create large pools of storage that can be made to appear as physical devices attached to a computer. Combine that with a virtual network in the cloud and you have a transparent source of storage to users and applications. Neither needs to know the details because to them, they are just accessing files on a disk drive on the computer.
The Virtualization Experience
To the user of a system, everything appears to work just as if the applications, storage, printers and network were all on or attached to their computer. In reality, none of that may be true. The user has the same experience doing their job while the administrators see some really tangible benefits:
- Equipment is consolidated, meaning less capital is spent, less maintenance is required, upgrade costs are reduced and overall data center operations time and costs are less
- Physical data center space required is reduced as well as all of the supporting infrastructure necessary (power, HVAC)
- Creates a high-availability environment without the need for purchasing larger systems
- Provides single-point disaster recovery scenarios by reducing all of the components that need to be restored
- Makes maintenance and backup easier throughout the enterprise
- Creates easier access to resources while providing better security and controls
Data Center Virtualization is the next step in combining all of the computing resources of a company into manageable units. The bulk of a data center may not even be located physically in a company. This allows companies to manage a much larger virtual data center with fewer highly-trained personnel.
This is a Guest Post by Matt Smith. Matt Smith is a Dell employee who writes to help raise awareness on the topic of Virtualization and other network management subjects.