Log files not compressing

Hi all! I have just noticed a problem with my logs files. Usually they are automatically compressed (gziped) regularly (usually every second day) depending on how large they are. However I have just noticed that they have stopped being compressed, so my logs are HUGE. The last time they were compressed was on the November 23. My /var/log/mail is now 58 mbs my /var/log/httpd/access_log is a whopping 1168 mbs my /var/log/httpd/error_log is a huge 768 mbs. The problem is that I don't know much about this process at all. I assume that it is a cronjob that automatically compresses the logs. How do I restart the compressing process? Thanks in advance, and regards from Denmark! Dan Eskildsen