Day 3 / Session 3

Virtualization using open source

It’s a pressing need in every data center and open source software is up to the challenge

Prakash Advani

Prakash Advani, Linux Practice Head-Indian Subcontinent, Novell talked about how companies can leverage virtualization on Linux.

But first he had a quote from author Mark Twain. “Twenty years from now you will be more disappointed by the things that you didn’t do than by the ones you did do.
So throw off the bowlines. Sail away from the safe harbour. Catch the trade winds in your sails.
Explore. Dream. Discover.”

The OS and virtualization can go hand in hand. Speaking about the situation at data centers, Advani said, “In order to maximize the performance of their services, and to ensure fault containment of workloads, many IT managers are choosing horizontal scaling adding specific services on dedicated servers to meet their growing business needs.” This allows managers to isolate workloads, but in planning for peak workloads, many underutilized servers are added to today’s data centers resulting in an exponential increase, or proliferation of IT resources and the management burden has also increased along with the expansion of the data centre. In this scenario increasing server utilization is desirable and for that virtualization is a potent weapon that lets you have your cake and eat it too.

Processor trends including multiple cores and built in virtualization are being leveraged by x86 server virtualization technologies that allow you to increase utilization and availability as well as respond rapidly while lowering costs and mitigating risk.

“Processor companies have reached a threshold of adding cores to the chip and they need to look at something which adds more value. The cores will keep rising and probably we will have 80 cores on one dye. But to stay with the problem, they have started supporting virtualization on their processors,” said Advani.

He went on to explain the underlying concept of virtualization with the help of two technology concepts—partitioning and abstraction. Partitioning refers to the separation of execution environments which can be done with either hardware or software. Abstraction refers to the recreation of a computer’s physical hardware characteristics through software.

“Virtualization then, is the use of partitioning and abstraction, to allow for the division and simultaneous sharing of a computer’s resources. Virtualization technology is a way of making a physical computer function as if it were two or more computers—with each non-physical or virtual computer being provided with the same basic architecture as that of a generic physical computer,” said Advani.

The main component of the virtualization layer is the virtual machine monitor, also called the hypervisor, which handles the isolation of virtual environments, and the management of the shared resources of the computer.

Novell Xen is an Open Source approach to virtualization with features such as paravirtualization wherein your OS knows that it is being virtualized which helps improve performance.

Virtualized scenarios are many and server consolidation was the first to be discussed. Here enterprises reduce hardware costs by moving underutilized application servers from physical hardware onto virtual machines. “The number of virtual machines that may be hosted on a single physical server depends on many factors, including the number of processors, the amount of memory, the disk storage space on the physical host server, and the amount of resources consumed by the virtual machines, but it is not uncommon to have 10:1, or even higher consolidation ratios for highly underutilized servers,” said Advani.

Virtualization will not solve all problems. One needs to manage the same number of operating systems, there is a potential single point of failure, you have to do manual patching and maintenance and track all virtual images. Licensing is also one of the major issues in terms of OS usage in a virtualized environment.

Finally Advani listed Novell’s advantages in this area including no additional cost per virtual machine and the company’s Interoperability Agreement with Microsoft.