I have made some further experiments: the bug is still occuring with the latest updates.
I have traced the problem down to the main apache functions. It is not a mod_ssl issue! What is actually happening, is that due to "a2enmod ssl", the server have to listen on two ports: 80 and 443. This activates AcceptMutex to synchronize running processes. And here some problem occures under Ubuntu 12.04 So an alternative way to reproduce is: $ a2dismod ssl $ echo "Listen 81" > /etc/apache2/ports.conf $ service apache2 restart $ ab -c 1000 -n 5000 http://localhost/ Changing the "AcceptMutex" config option causes different results. For example with: AcceptMutex posixsem i get all 5000 requests done without error. Then trying to run ab again causes apache to stop accepting requests. -- You received this bug notification because you are a member of Ubuntu Server Team, which is subscribed to apache2 in Ubuntu. https://bugs.launchpad.net/bugs/1028470 Title: apache2+ssl hangs on high load To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/apache2/+bug/1028470/+subscriptions -- Ubuntu-server-bugs mailing list Ubuntu-server-bugs@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-server-bugs
