Apache Server Debugging

Sunday 28 December 2014 by Norbert

One of our servers running Debian Wheezy was showing Segmentation fault errors at least few times a day. It was logged in  /var/log/apache2/error.log:

[notice] child pid 10671 exit signal Segmentation fault (11)

We've decided to investigate this further and temporary enable Apache backtrace using instructions in /usr/share/doc/apache2/README.backtrace

This is how we did the setup:

install apache2-dbg php5-dbg libapr1-dbg libaprutil1-dbg gdb
mkdir /var/cache/apache2/debug
chown www-data:www-data /var/cache/apache2/debug
vi /etc/apache2/conf.d/debug
CoreDumpDirectory /var/cache/apache2/debug
ulimit -c unlimited
(check using: ulimit -a)
service apache2 restart

wait for new segfault error:
grep Segmentation /var/log/apache2/error.log

and view using:
gdb apache2 -core /var/cache/apache2/debug/core

It turned out the problem was caused by using Apc user cache. Apc is working fine as Opcache, but it has troubles when using as user cache in it's version on Debian 7 Wheezy.

Universal Analytics

Wednesday 19 November 2014 by Norbert

We are now exploring the new Universal Analytics, which is a replacement for Google Analytics. It all seems to be just another update, but there is much more under the hood. You can now add a custom dimension and it can be anything, for example current weather.

How to add weather to Universal Analytics:


It's a clever mashup of Universal Analytics, openweathermap.org and www.geoplugin.com.



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