Amdump switches to the appropriate Amanda configuration directory, usually /etc/amanda/config, then attempts to back up every disk as specified by the amanda.conf file. Amdump is normally run by cron. See the amanda(8) man page for more details about Amanda.
If the file /etc/amanda/config/hold exists on startup, amdump will wait until the file is removed before proceeding with the night's backups. This allows the operators to delay the scheduled backups when the circumstances warrant, for example, if the backup tape device is being used for some other purpose. When on hold, amdump checks for the deletion of the hold file every 5 minutes.