In case somebody is wondering: Network Space 2 is set up by default to rotate old log files every 2 hours. This is especially annoying during night time because it spins up the harddisk loudly. It also shortens the life span of the harddisk unnecessarily. This behavior can be changed by modifying /etc/cron.d/logrotate -file:
# DO NOT EDIT THIS FILE - edit the master and reinstall.
# (/etc/cron.d/logrotate installed on Wed Jun 24 16:58:35 2009)
# (Cron version -- $Id: crontab.c,v 2.13 1994/01/17 03:20:37 vixie Exp $)
# Limit the log files sizes using logrotate every two hours
0 0-23/2 * * * root /usr/sbin/logrotate /etc/logrotate.tab