As of December 12, 2012, the following updates have been made to the Log History system. As a reminder, the log_history workspace contains detailed logs of all activity on your site. These logs are contain a complete history of all activity since the site was first provisioned, whereas detail reports on the Reports tab only go back up to 90 days.
Updates now in effect:
The log_history workspace and the log files within that workspace do not count against your site's disk quota.
The log_history workspace and log files can not be deleted.
The log_history workspace can be assigned to be accessible to any user you choose, with site administrators automatically having access. Note that the only actual permissions are only download and list.