Virtualization Can Save Substantial IT Dollars
Servers, Storage, Memory and Client Workstations Can be Virtualized
Jul 24, 2009
Dynamic memory contents can be moved to and retrieved from hard disks in milliseconds and this makes it possible for several applications to use the same physical memory at seemingly the same time. The extremely fast switching of contents between system memory and hard disk will not be noticed by human users each of whom feels that he or she is the only user.
Why is Virtualization Important?
Because several applications can use the same physical memory, it will not be necessary to install several machines to provide the memory resource needed for several applications to run at the same time.
Modern virtualization goes further and makes such intensive use of other computing resources also possible. In a typical organizational environment, a great part of computing resources tends to be wasted. Common examples are:
- Many desktop systems remain idle most of the day
- The CPU of servers and desktops is used sparsely even when computers are running
- Much of the hard disk storage capacity remains unused in many computers
Financial losses follow in several ways. Equipment has to be paid for, whether used or not. Power consumption does not vary much between a computer that is used flat out and one that is remaining idle most of the time. The large numbers of equipment generate a lot of heat, and cooling needs additional power..
Virtualization makes it possible to use the servers more intensively, running several applications under different environments. Desktops can be virtualized by using less expensive, low-spec workstations that push processing and storage to backend servers. The result is a great reduction in costs of equipment, power consumption and administrative costs.
How Does It Work?
In a virtualized environment it is possible to run different applications in the same server. One physical server will provide different virtual environments to users. One user will get a Windows XP environment, another Windows 95, a third will find an Ubuntu Linux setup and a fourth one finds a Mac, for example. This becomes possible because a software, called hypervisor, will be sitting between the hardware and applications, and translating the different system calls in a way the hardware will understand.
In effect, you will get several virtual machines (VMs) with one physical machine, allowing reduction of hardware used.
Desktop (or client) virtualization involves moving the processing and storage from desktops to the backend servers to which these clients are attached. This will mean that the client workstations can be low spec machines instead of full spec computers that cost much higher.
Storage virtualization involves moving the dedicated storage capacities attached to each physical machine to a separate storage facility, which might be located remotely. All the machines access this storage for storing and retrieving data. The uneven storage capacity utilization of individual machines will thus be eliminated.
It will now also become easier to enhance storage capacity as needed, something that would have been a complicated administrative exercise if individual machine storage capacities had to be assessed and enhanced as necessary. Other administrative tasks, such as installing operating systems, patches, antivirus software and other applications on individual machines can also be eliminated.
Result will be major cost savings.
The Technology Involved
The technology involved in virtualization is complex, and is typically done through installing software such as VMware. The software will have to:
- Swap memory and CPU contents, and Operating system states, between the system unit and hard disk as each new virtual machine comes into operation
- Ensure that each virtual machine is able to access only what belonged to it, and that there is no mixing of the data of several machines
- Control the access of each virtual machine to computer resources and data in a coordinated manner
- Control network data flows in a manner that the data sent by and meant for each virtual machine is correctly tracked and handled
These tasks can degrade performance as the number of virtual machines increase. A current virtualization technology focus is on moving some of these tasks to hardware, to the chips and chipsets. More details are available in the e-book Virtualization for Dummies downloadable free from Sun Microsystems.
Virtualization is a technology, delivered either through software or hardware, for enhancing the work capacities of physical computing resources. More intensive use of the physical resources leads to savings on several fronts - equipment costs, power costs and administration costs. Virtualization can thus result in substantial savings in IT dollars.
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