9.2 Database management

There are three operations that can be done on databases:

• Backup. This is also called dumping the database. There are two ways to do this - the obvious one is to use Berkeley database utilities such as db4.4_dump. This however requires locking the database in order to prevent modification during the backup, and at the moment the only way to do this is to shut down dgrey. Due to limitations in MTAs such as Postfix, dgrey usually has to be running all the time. To remedy this situation two commands were added to dgrey - dump-greylist-database and dump-awl-database. Here is how to use them with dgrey-cmd (from the example crontab):

            backupdir=/var/backups
            config=/etc/dgrey/config
            dgrey-cmd --config-file $config --local-connect dump-greylist-database \
              | gzip > $backupdir/dgrey-greylist-database.gz
            dgrey-cmd --config-file $config --local-connect dump-awl-database \
              | gzip $backupdir/dgrey-awl-database.gz
  

• Restoration. As with backup, one way to restore the database is to use a command such as db4.4_load. This requires dgrey to be shut down. Another way is to use the restore-greylist-database and restore-awl-database commands:

            backupdir=/var/backups
            config=/etc/dgrey/config
            gzip -cd $backupdir/dgrey-greylist-database.gz \
              | dgrey-cmd --config-file $config --local-connect --stdin restore-greylist-database
            gzip -cd $backupdir/dgrey-awl-database.gz \
              | dgrey-cmd --config-file $config --local-connect --stdin restore-awl-database
  

  Please note that these commands do not delete anything from the current databases, they only add to them.

• Maintenance. In order to optimize the Berkeley database and purge old records, maintenance has to be done. This is usually done daily, with the database-maintenance command.