|CMS (Teamsite)||Solaris||1||10,7,5||20,15,10||Testing shows this app to be responsive up until these loads.|
|Web Server||Linux||2 x 4||16,10,4||32,24,20||Web servers are paired, so want to know if reaching 50% capacity regularly. Testing shows performance degradation from a load of 20.|
|DB Server||Linux||2 x 4||16,10,4||32,24,20||Same hardware, different use. Nevertheless, using same thresholds.|
|Nagios||Linux||1 x 2||6,4,2||12,10,7||Small box, paired with backup.|
- The UNIX servers (particularly the Sun SPARC ones) seem to be able to stay up and responsive even under heavy load. And they don't count processes waiting for I/O in their load counts the way Linux does. I have no explanation for this. :-)
- We track these loads over time to predict demand growth for capacity planning -- the thresholds are not a long term goal but rather a short term alert threshold.
- Transaction or revenue-earning web servers might have lower thresholds because of the different commercial implications of performance degradation. YMMV.
For more information on the Nagios check_load command, see Tuning Nagios Load Checks.