Microsoft Knowledge Base Article 315098 contains the following summary:
You can use the online dbdump feature in Ldp.exe to view
the values that are stored in the database while a domain controller is
You trigger the online dbdump feature by modifying the dumpDatabase attribute on the rootDSA.
The values that you specify for this attribute are the attributes other than the default attributes that you want to dump. Note that the values that you specify are the name for this attribute. The dumpDatabase feature first checks that you have enough rights for dumping the database. It then dumps the database into the Ntds.dmp file. The Ntds.dmp file is located in the same folder as the database file (.dit). The default attributes are: