Stacy's Tech Blog

Some businesses I deal with regularly do not have any sort of virtualization technology in place. Many have a fair understanding of what virtualization is, but not necessarily how it can help the business.

What is virtualization?

There are many different perceptions of what “virtualization” means in the context of Information Technology. I will not delve into the super-technical aspects of various types of virtualization, but will attempt to break it down into key types along with how it could help your business.

Server Virtualization

In today’s context, a server can be two things.

1. A physical server, such as you might purchase from Dell, IBM or HP.
2. An operating system (OS), such as Microsoft Windows Server or Linux.

Traditionally, there is a one-to-one relationship between an OS and the physical server hardware. But with server virtualization, that relationship changes from one physical server (host) to many operating systems (guests or VMs).

Server virtualization is technology that specifically allows multiple operating systems to be run on a single physical server.

Example: Many businesses have several servers that provide something to the infrastructure. Email Services, File Storage Services, Printing Services, Authentication (Login) Services, Database Services are examples of the most common types. But installing all of these services onto a single physical server is not necessarily a good idea since these services could conflict with one another and cause problems. And having multiple physical servers for each of these services is costly, both in initial purchasing and ongoing maintenance costs, but is commonly done.

As long as the physical server hardware is capable, you can install a server virtualization technology, known as a hypervisor (such as VMware ESX, Microsoft Hyper-V or Citrix XenServer) as the “host”, then you can create multiple virtual machines “VMs” or “guests”, each running their own operating system and publish/provide services. These VMs then share the resources (processor, memory and hard drives) of the same physical server.

Benefits:

Server Virtualization benefits a business in terms of reduction in physical server costs and ongoing maintenance costs, depending on the configurations, and would allow for very flexible management. Also, the fewer physical servers you have, the less electricity you use and the less space is required to house them.

Centralized storage (a component often included with this type of solution) that can be used by multiple physical servers can increase the cost of the solution, however, it usually balances out in regards to overall cost as you are reducing the number of physical servers initially purchased. It also vastly improves performance if designed and implemented correctly in this context.

Application Virtualization

This is not a new technology since many vendors have been doing this for decades. But in the context of microcomputing today, it means you install an application on a server and then have users connect to that server over the network to run the application. The application then uses the server’s hardware resources (processor, memory and hard drives) to function and execute rather than a user’s workstation resources.

There are many different flavors of this technology, but the most common today are Citrix’s XenApp and Microsoft Terminal Services (which XenApp utilizes). This is technology installed to allow multiple users to connect and share the operating system resources (both hardware AND software) of the XenApp server.

Example: You install Microsoft Windows Server 2008 operating system on a server along with software to allow multiple users to connect and share the operating systems resources. Then you install the Microsoft Office Suite (Word, Excel, Outlook) on that server and “publish” the applications for your users. You then install a client software on each of your 25 workstations and direct it to the server. User’s can then connect to the server, run the application and the server does 98% of the work.

Benefits:

Application Virtualization benefits a business by centralizing the installation of end-user software and thereby lowering ongoing maintenance/upgrade costs associated with those applications. User workstations (desktop PCs) may not be required. It is possible to deliver these applications to alternate endpoint devices, such as a thin client or minimally installed desktop PC, thereby removing the costs associated with maintaining a user’s PC. Additionally, since the applications are installed on server-class hardware, performance is often improved.

Desktop Virtualization

This is something that has just recently (in the last year or so) started getting a lot of attention in the IT industry. You’ve likely heard the terms “Desktop Virtualization” or “VDI” tossed around from sales folks, literature or the Internet.

Desktop virtualization is much like Server Virtualization in that it is a way to share physical hardware. It means that you install multiple workstation operating systems (such as Windows Vista or Windows 7) into virtual machine “guests” on a server that is running a hypervisor. This hypervisor allows multiple operating systems to share the physical server hardware, much the same way as Server Virtualization.

As with the other types, there are multiple Desktop Virtualization solutions out there, such as VMware View and Citrix XenDesktop.

Example:

If you have 25 Destkop PCs, then they must be installed with an operating system, maintained, updated and repaired. A typical Desktop Virtualization solution for this scenario may be two physical servers, each with a hypervisor installed, and then a virtual machine is created and installed with the desktop operating system for each user. Users then connect to their Desktop VM and can work, with the server doing 98% of the work. The VMs are now “guests” on the physical server and share the server’s processor, memory and hard drives, just like server virtualization.

Benefits:

Desktop Virtualization benefits a business by centralizing, making it easier to upgrade, patch and support a user’s working environment. Desktop VMs are likely closely located to the servers that support them, making access to those services much faster. And like Application Virtualization, desktop PCs are not necessarily required as the Desktop VM may be delivered to an alternate endpoint device, such as a ThinClient, or a minimally installed desktop PC.

Synopsis:

Virtualization is essentially technology that allows the sharing of resources, both hardware and software.

What you choose to virtualize and the product you choose to use should always be tailored to your business. There is no “one size fits all” and there are many “what if” scenarios with deploying these types of solutions. Ask questions of your IT staff, consulting team or trusted technical advisors and ask for demonstrations.

It is possible to combine one, some or all of the types listed here and there are dozens of ways each of these types of initiatives may be designed, implemented and managed. The key is to ensure this is done in a balance that best supports your business.