ADSM keeps exactly the number of copies you specify for exactly as long as
you specify.  So, for a file log.n where n changes everyday, ADSM will make
a backup copy to the server of log.n once for each n.  If there is never
another log.1 there won't be any other files on the server with the name
log.1.  If there is another log.1, the first log.1 will be saved (if
verexists is greater than one) and called inactive and the newer version
will be saved as the active copy.  Active versions of the file, that is
files that exist on the client, remain stored on the server forever.
 Inactive file copies are kept the length of days specified by retain
extra.

So, if you want to keep any log file for three weeks and the log files have
different names everyday and you never delete them, any value for retain
extra and version exists will do since the file is always active.  If you
delete the log files regularly and you would like to keep the copy around
on the server then set retain only to the number of days you want to keep
the inactive and deleted on the client file.

If the log files have the same name everyday but are different, then you
would need to set version exists and retain extra to be the number of
versions/days to keep the file. For instance, your example of three weeks
would have version exists and retain extra set to 21.

ADSM only needs to backup data that has changed.  You will never have two
copies of a file on the server.  You can have a copy of the file the way it
looked today and a copy of the file the way it looked yesterday.  This
assumes you use the incremental command to perform the backup.  If you use
the selective command then you can have multiple copies of the same file.


Kelly Lipp
Storage Solutions Specialists, Inc.
lipp AT storsol DOT com
www.storsol.com
(719) 531-5926