Backup - Unchanged files

[RicochetPeter]

Hi all. While doing backups over time I have tried to analyse the space usage of these backups. What made me dig deeper is the fact that incrementals were constantly backing up rather old files... like
/var/www/web40/log/2006/12/web.log

looking at the stat output for this file:

Access: 2008-03-25 20:33:11.000000000 +0100
Modify: 2007-01-01 00:30:04.000000000 +0100
Change: 2008-03-26 00:30:06.000000000 +0100


The last access timestamp is the actual backup process (tar), but the change timestamp is a riddle to me... must be this ispconfig cron job:


30 00 * * * /root/ispconfig/php/php /root/ispconfig/scripts/shell/logs.php &> /dev/null


Does the log cron job do something to the "old" files, and every time it runs?

If yes, can that behaviour be changed?
If no, what else could it be?

[falko]

Does the log cron job do something to the "old" files, and every time it runs?

Yes, it greps all accesses for that web site from the overall Apache access log (in /var/log/httpd) and adds them to the web.log.

[RicochetPeter]

OK, so... I use tar with the --listed-incremental option. Does anyone know how to make tar backup only files that -in the wording of stat- habe been "modified", not "changed"?