I know, that there is much content on the site…
For test purposes I reduced the content to a third, but the load time didn´t really change.
This is the result:
Thanks for any help/suggestions.
I’d recommend doing a couple of things:
1 - Run several tests (3-5 runs at least) to see if it is an intermittent or persistent problem
2 - Try from multiple locations just in case there is a problem with the agent you are testing from
3 - Add server-side response-time reporting to your access logs (%D to the logformat for Apache)
There were a couple of requests for static objects (files that should just be served directly by the web server) in your test that took WAY longer than they should (4 seconds and 27 seconds).
I ran the tests a few more times from a few different locations and it certainly looks like you have a serious server configuration/performance problem. You could be running out of clients or something with the filesystem but your server configuration is running really poorly.