When you want your servers to perform at their best, Windows Server’s built-in performance monitoring and analysis tools offer insight into potential areas for improvement by letting you monitor current performance information and log this information over time. However, you must understand the core hardware performance factors of any server (i.e., Windows servers, Linux servers) to use the tools effectively.
The four key server hardware components that can be altered to improve performance are the CPU, memory, hard disks, and network interface card (NIC). Three of these components are internal (i.e., CPU, memory, hard disks) and the fourth component is the gateway to the network. Internal server performance determines whether the full NIC capabilities can be utilized, and NIC performance determines whether a well-performing internal system matters. As you can see, all four components are important and depend on one another.
In this article, I’ll cover these four areas of system performance and explain how to monitor them in Windows Server environments. First, I’ll explore how systems thinking helps you understand how these components affect one another. Then I’ll discuss the performance counters available in Windows as they relate to the four hardware components. I’ll also provide some recommendations for improving the performance of your system based on the results of performance monitoring.
Systems Thinking and Creating a Baseline
As you monitor and analyze Windows Server performance, it’s essential to employ systems thinking, which requires you to consider the relationships among the hardware components. For example, if CPU utilization is high, the CPU isn’t automatically seen as the problem. Instead, memory and hard disk utilization should be considered. Is the system using an excessive amount of virtual memory? If that’s the case, CPU utilization might be a symptom of a memory problem rather than evidence of an insufficient CPU speed.
I’ve performed analysis on hundreds of Windows servers and with all of this experience I’ve learned one important general guideline: faster CPUs don’t always solve performance problems. It’s tempting to throw more speed at the problem, but remember the old saying: If a man is lost in a city and he drives faster, he just gets lost faster. You could rephrase this saying for server performance tuning and say that a faster processor just loops faster while it’s waiting for the true bottleneck to finish working.
When analyzing the performance of a Windows server, you should analyze all four core components at the same time. Systems thinking indicates that you’re considering the system as a whole and not just evaluating a single component. Using the systems thinking process will enable you to locate the true performance bottleneck more quickly.
Before I begin exploring the performance counters, let me explain the need for a baseline. A performance baseline provides a representation of the system’s performance during acceptable operations. You can create a performance baseline by monitoring and logging performance counters during a period of normal operations. I prefer to monitor for an entire work window; for example, if the organization functions between 9 A.M. and 5 P.M., I’ll monitor during that entire time. Once you’ve created the performance log, you can open it in the Performance tool and narrow the viewing window to peak utilization times. If the server performed acceptably during peak utilization, you know that the server is well configured for your intended use.
As time goes by, the server is more heavily utilized in most implementations. Users become more familiar with the system and more productive, meaning they do things faster and place more demands on the server. Additionally, more users are often added to the system. All of these factors can result in a poor-performing system. You can create a new performance log and compare it with the original baseline to locate problem areas. As the counters are discussed in the following sections, remember to consider their use in and against a baseline rather than as simple point-in-time measurements.
CPU Counters
The Reliability and Performance Monitor in Windows Server 2008 and the Performance tool (sometimes called System Monitor, but displayed simply as Performance) in Windows Server 2003 R2 and earlier provide several important counters related to the four core components. The key CPU counters are listed under the Processor and Process objects. My favorite Processor counters are the % Processor Time counter, the % User Time counter, and the % Privileged Time counter. These three counters are available in the Processor object and can be monitored for all CPUs or specific CPUs, as shown in Figure 1. They’re also available in the Process object and can be monitored for all processes or individual processes.
If you notice that the % Processor Time counter is high in the Processor object, you might want to monitor it in the Process object for each individual process. Doing so will give you insight into which processes are monopolizing the processor’s time. You might choose to offload some of the processes to a different server or you might even be able to stop running some processes. It’s amazing how many unused processes often run on Windows servers and even these unused processes can impact performance as the Windows kernel must still manage them. Examples of unused processes include startup applications that aren’t used, services that are unneeded, and optional application components that run as separate processes.