Right now the cache module does not monitor the disk usage, user can clear up the cache directory regular with a cron job if needed. Should give enough disk space for it. We may add the feature to clean it up.
Cache file will stay on the disk until it was removed regardless lshttpd process status.
Right now, lshttpd only checks the expiration time which is part of header of each cache file, does not store number of hits there, only track it in memory, so if lshttpd restart, the hit counter will be reset. If store the hit count in the file, it will cause too many small random write which results in bad disk I/O performance. And it is difficult to keep it in sync among multiple lshttpd processes.