You are correct.  Actually the command is delete volhist type=dbbackup
todate=today-2.  This command would delete all db backups older than two
days.  It seems you are probably getting many more than one per day.  You
should probably consider:

Increasing the size of the recovery log or

Resetting your log mode to normal.  Roll Forward recovery lets you restore
your ADSM environment in the event of a database failure to the most
recently committed transaction.  If you use normal mode instead, you can
recover ADSM to the state of the server at the time of the last database
backup.  This means you could potentially lose all of the transactions
since that backup.  In the case of backup data this might be OK since the
next time the client performs an incremental backup operation, data that
had been backed up but lost will be backed up again.  Obviously if the data
is lost on the client too, you've got a problem.

Roll Forward is neat but I've found it to be a pain in the butt.  If you
perform operations like archive and then delete the data, you might need to
use Roll Forward.  Or use Normal, archive the data, wait until the next
ADSM backup db command and then delete the archived data.

Kelly