The BACKUP command operates at the location level, including all paths and files for all tables in the location. Likewise, the ROLLFORWARD command, which applies the current series of location log files to a backup copy of the location data, also operates at the location level. If you have more than one database in a location and only one of those databases needs to be restored and rolled forward, you still have to restore and roll forward all of the databases in the location.
If you use an operating system backup command or other backup utility, and you intend to use the location's log files to reconstruct the data for that location, be sure that you have backed up all the files in all the paths that are defined for the location, including stogroup paths, if any. Also, be sure to reset the location logging after each backup is completed.
If your location backups are infrequent or if activity is high and the number of log files grows rapidly, you may wish to back up your location log files periodically to ensure that logging is available if you need it. Use an operating system BACKUP command or utility to back up the log files.