Backing Up Oracle - Computing at Cornell

Note
You should assume that import will work only with files that have been
created by the same RDBMS's export utility.
Most other utilities operate on the physical data files that RDBMSs use to
store their databases. Therefore, other utilities cannot normally be used to
back up and restore a single table because:
A single physical data file may contain data belonging to several tables.
The data contained in a single table may be spread across multiple data
files.
Thus, the only way to gain access to the set of data contained in a single
table is through the RDBMS itself.
Export utilities are usually slower than most other utilities and should be used
only when you need access to database objects or raw devices.
3.2.5 Full database backup
Full database backups involve making copies of:
Data files used to hold user data
Data files that hold tables used by the RDBMS itself
RDBMS log files
Any control files and parameter files that the RDBMS uses
Many RDBMSs allow you to perform full database backup when the database
is either online or offline. However, the technique for full database backup
when the database is online can be quite different from offline.
To perform offline backup, you can use the operating system utilities, RDBMS
utilities, or TSM to back up the data files that constitute the database. To
perform online backup, you need to use an RDBMS utility to create data files
containing a copy of the database. You can then use TSM to back up these
data files along with the parameter files that you use to start up the RDBMS.
The simplest approach to database backup is to perform only full, offline
backups at regular intervals. This approach is relatively easy to administer,
and recovery is relatively straightforward. However, it may not be practical to
take databases offline for the period of time that is necessary to perform full
backups at the frequency you need. You may have to adopt a more flexible
approach.
28 Backing Up Oracle using Tivoli Storage Management