Unix Backup and Recovery

Physical Backups Without a Storage Manager

Storage managers can be very expensive, so they are not always available for every application. Even if you have a storage manager, you may not want to spend several thousand dollars per server for the Oracle interface. This section discusses methods that can be used to safely back up Oracle without using a storage manager. You can back up to disk and then back that disk up using your normal backup procedures, or you can back up directly to tape.

Like most RDBMSs, Oracle databases can reside on cooked filesystem files or raw disk devices. Unlike Sybase and Informix DBAs, though, Oracle DBAs typically have put their databases on cooked files. There is a very good reason for this: if all of the database files are accessible via the filesystem, backing up is very simple. That is because copying the data can be done by any standard copy (cp) utility or backup (dump, cpio) utility.

Backups can be done offline (a cold backup) or online (a hot backup).

Cold Backup

A cold backup of an Oracle database that is based on filesystem files is the easiest of all database backups. This is because most companies already have some system that backs up their filesystem files. It could be a homegrown program that runs dump, or it could be a commercial backup product. To perform a cold backup of an Oracle database, simply shut down Oracle before running the normal backup. Oracle will do a checkpoint, flushing any data stored in memory to disk, and then stop all ...