Virtualization: Popular among developers and enterprises

NEW DELHI: Innovation is the key driver for IT industry. From age-old 286 to the Pentiums and dual-core PCs, from 5 ¼ floppy disks to pen-drives, from sturdy-looking desktops to the slick PDAs and palmtops-- constant innovation, not only at the hardware level but also in the software space has done it all. Virtualization software is the result of one such innovation.

Loosely defining, virtualization is a framework or methodology of dividing the resources of a computer into multiple execution environments. By installing virtualization software one can run multiple operating environments on the same hardware, with each one using the all the resources of the underlying hardware. According to the official VMware website, "virtualization is an abstraction layer that decouples the physical hardware from the operating system to deliver greater IT resource utilization and flexibility."

So, how is virtualization different from partitioning? While in partitioning the hardware resources like processors and hard disks are allocated to different operating systems, in virtualization the entire hardware profile from the processor to hard disk to RAM is available to all the operating environments. Each operating system runs in its own virtual environment on a virtual machine, and is actually oblivion to the presence of the other.

Introduced in 1960s to partition mainframes, which were then a very expensive resource, virtualization lost its essence with the introduction of efficient PCs and minicomputers. However, in early 1990s there was renewed interest in it, as researchers felt that it could be the answer to problems like data proliferation, under-utilization and rising costs.

Benefits of virtualization

Main areas where virtualization is of immense use are enterprises, software development companies and Internet service providers. Enterprises incur lots of expenditure because of under-utilization of resources. Using virtualization, idle resources of a server can be used to run applications on a virtual machine. Server proliferation, a problem that arises because of increasing numbers of servers can also be tackled by virtualization. For software development companies where development happens on various operating systems like .Net, J2EE, Linux, Unix etc. installing virtualization software can enable different operating environments on the same machine. The same technique can be of immense use to software testers who need to test their application on various operating systems. For ISPs also this is a useful technology, they can maintain hundreds of mailboxes virtually on the same server without their customers getting to know about it. Running several mailboxes on the same server allows full utilization of the server's resources and easier maintenance.

Just watch-out!

Like all good things, this technology also has certain aspects that need to be watched out. The underlying physical server being a single entity, lots of care has to be taken to maintain it, because if that crashes the entire system can go for a toss. Deploying fail-over clusters for mission-critical applications is one of the many available solutions. Proper server management is the backbone of virtualization, because a resource heavy application can pull all the available resources bringing down the performance of other applications.

Operating in the 'virtual' space

Prominent names in this space are Microsoft and VMware, an EMC company. Microsoft products include Virtual Server and Virtual PC. Virtual Server is a solution designed for Windows Server 2003 to increase operational efficiency in software testing and development, server consolidation scenarios, and application re-hosting. Using Virtual PC, multiple PC-based operating systems can run simultaneously on one workstation, providing a safety net to maintain compatibility with legacy applications while migrating to a new operating system. For details on Microsoft virtualization products, check out: http://www.microsoft.com/windows/virtualpc/default.mspx and http://www.microsoft.com/windowsserversystem/virtualserver/default.mspx.

Under Vmware's product umbrella come VMware Workstation, a desktop virtualization software for software developers and testers. VMware GSX Server, which can be used to transform physical computers into a pool of virtual machines by isolating operating systems and applications in multiple virtual machines that reside on a single piece of hardware. VMware ESX Server, a virtual infrastructure software for partitioning, consolidating and managing servers in mission-critical environments and VirtualCenter that can be used as a central point of control for data center's virtual computing resources. Visit http://www.vmware.com , for details on VMware products.

Another not be missed out name is XenSource, an open source virtualization solution provider. Xen, is an open-source virtualization tool that allows multiple operating system instances to run on a single physical client or server. Xen 2.07 supports Linux 2.4 and Linux 2.6-based kernels from major Linux distributions, as well as NetBSD and FreeBSD. Visit http://www.xensource.com/, to know more about Xen.

To read PCQuest's cover story on Virtualization, click here.