I am running Apache/2.4.18 (Ubuntu) and experience now extreme long response rates, even time outs. After restarting the apache server, everything is back to normal for a few days until it starts happening again.
The pages eventually load and once loaded, I can browse through the page without delays, but once changing IP or sometimes to anonymous browser mode it will again take 20+ s until the page loads, then again in the same browser window works OK.
Restarting the apache server solves the problem for a few hours/days, but I could not detect the root cause. Apache logs look OK.
What could be the problem causing this or how could I narrow down the problem in order to fix it?