Virtual Architect

Which Servers Should You Virtualize?

To combat the pain of PerfMon, there are a number of tools that help.

When it comes to virtualization candidacy, it's all about one word: performance. To that end, the only true way to determine whether a physical machine will make a good VM candidate is to take a look at its overall performance over an extended period of time. With Windows systems, the only real way to measure performance is by looking at performance counters exposed through the Performance Logs and Alerts console, commonly called PerfMon.

One challenging task with PerfMon is in distilling through the hundreds of potential counters to find just the ones you need. However, using PerfMon remains a challenging task, even with the correct counters. Working with its database files, understanding their idiosyncrasies and ultimately creating useful reports is complicated to the point of absurdity. This challenge often inhibits administrators from successfully using PerfMon as a tool for validating candidacy.

To assist, a number of solutions are available that layer atop Windows' native performance counters. These tools take the pain out of preparing reports and creating actionable suggestions about which servers should be virtualized. One of the very first solutions to this end is a type of Software plus Services contract called Capacity Planner from VMware.

Capacity Planner
Capacity Planner leverages a locally installed Data Collector that monitors the behavior of systems on the local network, and transmits the resulting information to a centralized data warehouse over the Internet. Within this centralized location, numbers are crunched and reports on candidacy are made available for review. Once monitoring has run for a period of time, VMware consulting services can assist with the interpretation of the results and with planning the conversion.

The downside of the Capacity Planner approach is cost. Because of this, VMware also provides an option called VMware Consolidation.

This solution looks at a more limited set of performance characteristics, focusing mainly

on processor and memory usage on targeted systems. The reports it provides are similarly limited in scope, showing you only the servers being monitored along with a confidence level that the virtual host can support their needs. Because of its limited information set, this tool is handy for small environments with few candidates.

MAP Solution Accelerator
Microsoft offers another no-cost product that assists with the candidacy-determination process. The multifaceted Microsoft Assessment and Planning (MAP) Solution Accelerator is used for assessing Windows computers in an environment with an eye toward their ability to fulfill a number of stated roles.

MAP inventories machines to look for the capability to support Windows Vista, Microsoft Office 2007 and Windows Server 2008, along with other readiness assessments. The assessment process, which is designed to run for an extended period of time, looks at performance characteristics on identified servers. Once an acceptable amount of time has elapsed and enough data gathered, the tool makes available numerous reports. For a free tool, the reports are impressive.

Third-Party Help
If your environment requires an even more comprehensive solution, products for managing and monitoring performance are also available through other vendors. PlateSpin's PowerRecon, for example, is one tool designed to collect performance information from both physical and virtual servers and use that information along with built-in intelligence to make educated decisions on virtual machine placement and best use of resources. CiRBA also has a comprehensive data center intelligence software suite that, among other functions, assists with the candidacy-planning process across multiple virtual host and machine platforms. These are both full-featured, enterprise-level products designed to assist across the entire virtual server lifecycle.

About the Author

Greg Shields is Author Evangelist with PluralSight, and is a globally-recognized expert on systems management, virtualization, and cloud technologies. A multiple-year recipient of the Microsoft MVP, VMware vExpert, and Citrix CTP awards, Greg is a contributing editor for Redmond Magazine and Virtualization Review Magazine, and is a frequent speaker at IT conferences worldwide. Reach him on Twitter at @concentratedgreg.