How do I fine tune the performance and resource consumption for FKM plugin?

1. Identify any problematic sampler or log file

Users can have multiple log files being monitored on each server. The application behaviour may also change depending on usage and time of the day. It is not always easy to tell which is the problematic sampler or log file should the Netprobe take long time to process.

The SAMPLING debug option may be enabled for such cases. In Gateway Setup Editor, select Probes => (Probe Name) => Debug tab. Then press the Add New button, and add SAMPLING with Setting * as in the screen capture.

The netprobe log will then contain the start and end times when a sampler is executed. This will help identify if a certain sampler taking a long time to finish.

2. Review FKM keys

- If the FKM keys are configured to use regular expression (regex), the performance can have big difference depending on the regex pattern configured. In particular, look out for the generic catch all pattern .* and avoid putting this near the beginning, which can cause unnecessary "backtracking" and therefore poor performance. There are many articles on this topic in the internet, which can be found with keyword regular expression backtracking.

- Arrange order of FKM keys from specific to generic patterns. There is a separate article on order of FKM keys in our web site: Does the order of FKM Keys impact performance?

3. POSIX vs PCRE regex option

The FKM plugin can select to use POSIX or Perl Compatible Regular Expressions (PCRE) syntax for regular expressions. Users can check out the FKM Configuration doc (Notable differences between POSIX and PCRE) for differences between the two.

If you do not use regex syntax specific to POSIX or PCRE, you may try toggling the parameter and see any performance improvements. The checkbox option is located at FKM plugin's Advanced tab: Use PCRE Perl Compatible Regex.

Note: The FKM plugin had POSIX as default in older versions of Netprobe. But the default has switched to PCRE since Geneos version 5.4.x (COL-7588).