Any system administrator who has been in the business for any length of time can probably tell you how to back up the home directories on any system. Start asking about backing up databases, though, and even the most seasoned veterans may start to squirm. To many administrators, the architecture of a database is a mystery. Unfortunately, you really need to understand how the database works to properly recover from a disaster. They know how to back up a filesystem, but ask them to find the backups for data space A in database B in instance C, and they look at you with fear in their eyes! They just don’t have any experience in database design—nor do they have time to get that experience. If they work in a heterogeneous shop with more than one database, it gets even harder. Their only hope is that the database administrators (DBAs) know what they are doing.

DBAs spend much of their time normalizing databases, designing user forms, and making sure the database performs adequately. They know how to back up their database disk, maybe even to a standalone backup drive, but they don’t have any experience with commercial backup software or large, automated libraries. If the database is too big to back up to disk and they don’t have a standalone backup drive to back up to, they have to work with the system administrators (SAs) to get the backup done. Their only hope is that the SAs know what they are doing.

Database products also differ from one another. Try to get an Informix DBA and an Oracle DBA to agree on what a tablespace is!^[53] One of the reasons this is difficult is that different products use the same term for different logical elements. What Informix calls a tablespace, Oracle calls a segment. Don’t confuse that, however, with a Sybase segment, which is closer to what Oracle calls a tablespace. Are you confused yet? Don’t worry.