AH00161: server reached MaxRequestWorkers setting, consider raising the MaxRequestWorkers setting

Question

I\'ve got a quite busy server: PHP (Wordpress) using W3TotalCache APC, Varnish for Apache and Cloudflare to handle all traffic. Ubuntu 14.04.4 LTS

Only one website with

Answer 1

In my case I couldn't find any solution, so I'm going to leave this answer here to help anyone else having this issue. In our case, increasing the MaxRequestWorkers didn't help.

We had a server that had been working fine for one year at least. All of a sudden, it began to have issues to connect to https. In the apache error logs, we found a "Server reached MaxRequestWorkers" error, but the traffic was very slow (30 - 40 visitors active).

After a deep look at logs and some research, I found that the issue was a Slowloris DoS attack.

The attack is easy to mitigate. You could take a look at this post.