Hi, we did some more testing and googling and foud thet this issue is discussed on apache-dev mailing list. They mention that the problem is related to proxy setting, and yes, we use mod_proxy too. There are some patches too. http://www.gossamer-threads.com/lists/apache/dev/355044?page=last We did strace, the last line is: futex(0x4447a700, FUTEX_WAIT, 2, NULL if you want I can send the whole strace -- Regards Vladislav Kurz