Performance

Check underlying system

1. Is there enough memory? There should always be at least 1 - 2GB free memory in production to avoid using swap space
2. Is CPU Usage high? Then check the CPU Usage guide
3. Check network performance via ICMP ping and Browser developer tools network tab - Response times of < 250ms are good and < 1s are acceptable.
4. Check the following resources for identifying lower level bottlenecks.

   -   <http://www.brendangregg.com/usemethod.html>  
   -   <http://www.brendangregg.com/linuxperf.html>  
   -   <http://techblog.netflix.com/2015/11/linux-performance-analysis-in-60s.html>