Server virtualization is the masking of server resources including the number and identity of individual physical servers, processors, and operating systems from server users. The intention is to spare the user from having to understand and manage complicated details of server resources while increasing resource sharing and utilization and maintaining the capacity to expand later.
Virtualization allows multiple operating system instances to run concurrently on a single computer; it is a means of separating hardware from a single operating system. Each “guest” OS is managed by a Virtual Machine Monitor (VMM), also known as a hypervisor which is computer software/hardware platform virtualization software that allows multiple operating systems to run on a host computer concurrently.
Because the virtualization system sits between the guest and the hardware, it can control the guests’ use of CPU, memory, and storage, even allowing a guest OS to migrate from one machine to another.
Virtualization is a modified solution between centralized and decentralized deployments. Instead of purchasing and maintaining an entire computer for one application, each application can be given its own operating system, and all those operating systems can reside on a single piece of hardware. This provides the benefits of decentralization, like security and stability, while making the most of a machine’s resources.
Advantages of Virtualization
Zero downtime maintenance
Freedom from vendor-imposed upgrade cycles
Pooling hardware resource
Virtual hardware supports legacy operating systems efficiently
Dynamic resource sharing
Security and fault isolation
Business continuity, backups, and automated restoration
Examples of Productivity Using Virtualization
When to use Virtualization
As virtualization disentangles the operating system from the hardware, a number of very useful new tools become available. Virtualization allows an operator to control a guest operating system’s use of CPU, memory, storage, and other resources, so each guest receives only the resources that it needs. This distribution eliminates the danger of a single runaway process consuming all available memory or CPU. It also helps IT staff to satisfy service level requirements for specific applications. Since the guest is not bound to the hardware, it also becomes possible to dynamically move an operating system from one physical machine to another. As a particular guest OS begins to consume more resources during a peak period, operators can move the offending guest to another server with less demand. This kind of flexibility changes traditional notions of server provisioning and capacity planning. With virtualized deployments, it is possible to treat computing resources like CPU, memory, and storage as a hangar of resources and applications can easily relocate to receive the resources they need at that time.
Components of Virtual Infrastructure
Bare-metal hypervisors to enable full virtualization of each x86 computer.
Virtual infrastructure services such as resource management and consolidated backup to optimize available resources among virtual machines
Automation solutions that provide special capabilities to optimize a particular IT process such as provisioning or disaster recovery.
Physical to Virtual Server Migration
Any respectable virtualization solution will offer some kind of P2V (Physical to Virtual) migration tool. The P2V tool will take an existing physical server and make a virtual hard drive image of that server with the necessary modifications to the driver stack so that the server will boot up and run as a virtual server. The benefit of this is that you don’t need to rebuild your servers and manually reconfigure them as a virtual server—you simply suck them in with the entire server configuration intact!
So if you have a data center full of aging servers running on sub-GHz servers, these are the perfect candidates for P2V migration. You don’t even need to worry about license acquisition costs because the licenses are already paid for. You could literally take a room with 128 sub-GHz legacy servers and put them into eight 1U dual-socket quad-core servers with dual-Gigabit Ethernet and two independent iSCSI storage arrays all connected via a Gigabit Ethernet switch. The annual hardware maintenance costs alone on the old server hardware would be enough to pay for all of the new hardware! Just imagine how clean your server room would look after such a migration. It would all fit inside of one rack and give you lots of room to grow.
As an added bonus of virtualization, you get a disaster recovery plan because the virtualized images can be used to instantly recover all your servers. Ask yourself what would happen now if your legacy server died. Do you even remember how to rebuild and reconfigure all of your servers from scratch? (I’m guessing you’re cringing right about now.) With virtualization, you can recover that Active Directory and Exchange Server in less than an hour by rebuilding the virtual server from the P2V image.
Software Automation Solutions for Virtualization
These are the few platform virtualization and software providers in the market on which organizations rely upon.
»»VMWare »»RightScale »»eNomaly »»Force.com »»Gigaspaces »»Citrix »»Xen »»Microsoft Virtualization »»Sun VirtualBox »»IBM PowerVM »» Hewlett-Packard Integrity Virtual Machines (Integrity VM).
Future Trends in field of Virtualization
Virtualization has significant cost benefits for organizations: server consolidation can yield a saving of ?2 million over three years for an organization running 250 dual-core servers; and a power saving in the order of ?78,000 per 1,000 PCs per year can be realized by moving from a full desktop PCs infrastructure to a server-hosted desktop virtualization solution.
The market for virtualization management solutions will be the most innovative and, potentially, lucrative in the near future.
Financial analysts estimate the market for IT virtualization could be worth over $19 billion.
As many as 16 million desktops could be virtualized by 2011.
The virtualization infrastructure management (VIM) market is undoubtedly going to be the most lucrative aspect of IT virtualization in the longer term, and so is perhaps the most dynamic and active part of the virtualization scene
Emerging trends and the evolving vendor landscape By Victoria Furness
Introduction to server virtualization by George Ou