Apache: Disable HostNameLookups

After an upgrade to our infrastructure (see a picture here), the delivery of content through apache was incredible slowly - the reason was that we moved our DNS servers to an external location and had no internal server for this task any more.
After some research we found out that disabling the host name lookup (HostNameLookups = Off) helped to speed up the pages delivery. Now our analyzer will perform the lookup task and we're happy again ;-)

JRUN crashes after changing the hostname of a machine

Yeasterday we updated our system and renamed a server from www-4 to www04 in our internal DNS system. After that, this server started to deliver pages very slowly (with a very low load, however) and after some reasearch we found out that chaning the hostname was responsible.
So make sure your internal hostname and the hostname set in /etc/hostname is the very same!