Forum OpenACS Q&A: Re: Backup script doesn't get sourced
Please see the script linked in the first message. I think it meets your requirements. There is, however, nothing related to scheduling nor making these backups in the log file. That is, I-search with "backup" in emacs doesn't give anything.
The script file has tcl extension. I have OpenACS 4.6, updated from cvs last time yesterday.