proftp log and large log files

regarding virtualmin pro 3.31

I wanted to create a seperate log file for all ftp transfers. So I went into webmin/servers/proftpd server and clicked on logging options.

It appears it is currently logging to the default system log.

My first question is if I want to log to another file, say /var/log/ftp-transfers what do I need to select? the choices are "default" "logging disabled" and then a box is the box the path to the file /var/log/ftp=transfers ? I would really like to do it on a per user basis, but all ftp trasnfers would be ok too.

the reason I want to do this, is so when a file comes in I can take that file and rsync it to another location, plus rename it and things like that, maybe therre is a better way to do this. I have been trying to use inotify to do this, but then I thought the names of the files should be in the logs.

if it is, then what is the other box below under custom log files? seems like there is something missing.

the other thing I noticed when I was looking for at the default system log was the size of the file. The xferlog is 34 megs, and I think that is the one the ftp transfers are being logged to. Is that too big for a log file. I also noticed other files like maillog being 118 megs and secure.2 is 87 megs, and secure is 80 megs, these seem rather large, are they ok or am I supposed to roll those logs over once and a while or something.