Server Virtualization to Improve ROI
Using a Virtual Infrastructure for Business Benefits
© Jeff Sue
Mar 12, 2009
Many, if not most, organizations limit the number of applications on their servers to a single application. This is especially true in the Windows Server environment where it is very rare to find businesses running multiple applications on a single server.
Back to the Future of Server Sharing
Originally computers were very large and expensive, meaning that companies had to share their costly investments across many business units. These computers typically ran mainframe operating systems like IBM's MVS, or Digital Equipment Corp.'s (now HP's) VMS/OpenVMS and VMscluster platforms. It was not uncommon to have hundreds of applications on these servers, with thousands of users.
But the important facets that allowed these platforms to be successful running so many applications is their reliability: both reliability of the hardware as well as the operating systems. Another critical aspect that allowed them to work so well in this environment was their ability to share the limited resources available. There were many features to allow companies to manage and control resource consumption.
Cheap Hardware Begets Tactical Thinking
With the advent of relatively cheap hardware - Windows servers were typically in the $20-50,000 range vs. $500,000-multi-millions for mainframe-class platforms - server proliferation resulted. Since only single applications were typically affected by outages, quality became less important as well as the capabilities to manage resource sharing among business applications. Cheap systems could be purchased at lower levels, and usually with very little strategy and planning.
Datacenter Capacity Management Problems Arose
Along with this server sprawl, the footprint within datacenters grew exponentially, finally bringing some of the hidden costs - floorspace and cooling - out into the open. Unfortunately, due to the laws of physics that made resolving these issues very problematic too. Although average server utilization numbers in the 10%-20% range did not motivate many companies, new datacenters, which are very costly, forced them to face reality.
Consolidation of Server Hardware Through Virtualized Servers
This has helped server virtualization become a critical platform on which to deploy applications - on what are now called virtual machines (or VMs). Instead of 10, or 20 servers, a company can buy one or two large servers and run applications on VMs, sharing the same hardware. Typically around 80% of an environment can be virtualized, but often this 80% can achieve densities of 10-to-1, or even 20-to-1.
Better Return on Investment Tags Along too
The densities of 10:1 or 20:1 can be possible because of the way that most application workloads fluctuate their demand for resources. By analyzing performance characteristics of a company's application workloads, it is possible to mix them in ways to achieve greater densities. This means that the ROI can go from a 10% or 20% number to a much better 70%. This is a significant improvement for the business.
Re-Inventing the Mainframe Services Capabilities
Once more application workloads reside on the same server hardware, higher-end IT services become critical once again. Many of these services are available in the solutions, depending on the server virtualization platforms deployed. Some examples of critical services returning to the business include:
- better server resource management - some virtual server platforms allow limiting the amount of CPU processor, memory, disk and network bandwidth available to an application's workload
- dynamic resource balancing - some virtual server platforms allow the coupling of physical servers in such a way that application workload VMs can be migrated on-the-fly to other servers to balance out demand - allowing all available hardware to be managed as a "pool"
- capacity management - what was once a common practice is now becoming critical once again, and the ability to manage overall capacity of hardware resource pools makes this easier to do
- online backup - with some virtual server/infrastructure platforms this is very easy and safe to do
- resource optimization - some platforms are allowing VMs to share parts of memory which are identical, reducing the need to have multiple copies of the same information in memory for each VM
Several Virtual Platforms Available
Two of the more common virtualization platforms in use today are from the following vendors:
There is also virtualization a product from Citrix, By far, VMware seems to be the most mature platform for virtualization right now, offering the most robust sets of services for managing resources.
