Are you logging in to your virtual server console -- either directly or through Remote Desktop Services (RDS) -- for daily, administrative tasks?
If so, stop! This seemingly innocuous practice of server console administration is singlehandedly reducing the performance of your entire virtual environment. Here's why.
Whether a logon occurs at the server console or through a Remote Desktop Protocol (RDP) session, it consumes RAM resources. An RDP session into the server, for example, requires the creation of at least four processes:
- explorer.exe (the shell);
- tasking.exe (the task scheduler engine);
- dwm.exe (the desktop window manager); and
- rdpclip.exe (the RDP clipboard manager).
The memory consumption of these four processes can change wildly over time, but they can also total as little as 10 MB of RAM per session.
Running an administrative toolset, though, consumes much more. The administrative server console for Microsoft System Center Virtual Machine Manger, for example, can use more than 100 MB of RAM, further taxing the core shell's resources.
Also, consider the activities involved with the logon process, because they tend to consume large amounts of system resources. During a server console logon, it's not unusual for processor utilization to spike to nearly 100% until the login finishes and control is relinquished to the user.
While these numbers may seem insignificant, two factors combine to exacerbate console-based administration problems:
- The effect of consolidation. If your server consolidation goal is 10 to 20 virtual machines (VMs) per host, that number must be multiplied by your consolidation ratio to recognize your true level of wasted resources. This amount can grow very large, ultimately affecting the consolidation ratio (and your virtualization project's return on investment).
- The patterns of use by administrators that engage in server console administration. These administrators tend to log on to servers and remain logged in for extended periods of time, which is not a best practice from a security perspective. Extended logons reserve available resources for administrative tasks instead of VM workloads.
Solving this problem is easier than you'd probably think, however. It involves only a slight shift in your use pattern.
Microsoft and many other software vendors typically build their products around a client/server approach: The goal of the server side is to complete workloads, while the client side focuses on management. For many applications, client-side management can be accomplished from a desktop. Microsoft's Remote Systems Administration Toolkit is available for common Windows activities, and System Center and third-party products have their own administrator consoles, which are designed to install to desktops as well.
Now more than ever, Microsoft is embracing the "stay off the server console" philosophy in many of its newest products. Before, administrative tools were automatically installed with the server components. Now these tools are in a separate installation.
If you're an IT old-timer who still engages in the ancient practice of server console administration, consider yourself warned. You're only wasting portions of your precious and expensive virtualization investment. Change now, and save the VMs!
This was first published in March 2010