Evaluating Memory and Cache Usage

After determining that you have an adequate amount of physical memory and that your configuration is appropriate, examine your physical memory usage under a normal workload to establish a baseline or reference point for physical memory usage. The baseline is generally not a single value but a range within which physical memory usage can fluctuate and still provide acceptable performance. You can use the baseline to identify trends, such as increasing physical memory demands over time, or to recognize problems that arise from a sudden change.

To determine a baseline for your system, use the following counters to create logs of memory usage over an extended period (from several weeks to a month).

  • \Memory\Pages/sec

  • \Memory\Available Bytes

  • \Paging File(_Total)\% Usage

As you monitor the values of these counters, you might see occasional spikes. Typically, you can exclude these from your baseline because it is the consistent, repetitive values with which you are most concerned; the range of values that seem to appear consistently constitutes your baseline. When values fall outside of these ranges for extended periods, follow the instructions provided in this chapter to investigate the variations.