I recently noticed a strange behaviour. I could not restart a productive webserver running since more than a year because the configuration was invalid:
# /etc/init.d/apache2 restart Syntax error on line 161 of /etc/apache2/apache2.conf: Invalid command 'Order', perhaps misspelled or defined by a module not included in the server configuration Action 'configtest' failed. The Apache error log may have more information. ...fail!
After further investigation I found a couple of files unter
/etc/apache2/mods-availabe to have a file size of zero bytes
... -rw-r--r-- 1 root root 0 Jun 15 15:14 authz_host.load ....
Is this an indication of file system corruption? I'm afraid to umount the filesystem in order to run fsck. Of cause the system is backuped but how can we spot something like this in the future?