If your server is exposed to the outside world acting as a web-server with a lot of websites, then IIS will be creating a lot of log files in the LogFiles directory. These log files can be safely deleted or backed up according to your compliance.
I came across a handy Windows script file (WaRmZip) that is an utility for cleaning, deleting, compressing and moving log files. You can download it at Winadmin tools web site: http://winadmin.forret.com/scripts/warmzip
This utility is to delete older IIS log files. Go to C:\Windows\System32\LogFiles or C:\WINNT\system32\LogFiles directory on your server. The folder location will change based on the OS. You may be surprised to find hundreds of files in each of the subfolders. Using the WaRmZip utility, you can remov these log files, and then schedule this batch file to run weekly or monthly.
– waRmZip.wsf /r “C:\Inetpub\ftproot” /da:7 /df /dr /log:c:\Inetpub\ftp_cleanup.log
– WaRmZip.wsf “C:\Windows\System32\LogFiles” /da:7 /r
In the second example, the da:7 option says to delete files older than 7 days, the /r option says to process all sub folders.
Once the script is ready, you can schedule it using windows scheduler and make it automatic. More script examples can be found on the winadmin site.
A GUI version of the similar tool can be found at http://www.iislogs.com/