We just had a situation on one of our Exchange 2010 CAS/Hub Transport servers where we almost ran out of C: drive space. After doing some checking, I found the culprit to be the IIS logs. The log directory had over 62GB of logs dating back almost 2 years. I deleted a lot of the older logs to free up some disk space. I checked the settings under IIS for logging and they are not very flexible. I was hoping there would be an option to flush logs after a certain amount of days. The only option I see is Disable. I would like to do some logging I guess but I don't want to baby sit this directory all the time either. Logging is enabled by default but is it better to just disable it and turn it on when you need it? If it needs to run all the time, is there something I can do to keep the amount of disk space it takes up to a minimum like circular logging with Exchange.