This module introduced you to various methods of performing physical backups with and without archiving.
You learned how to do open and closed database backups.
You also learned the importance of frequent and regular database and tablespace backups as essential strategies for any recovery scheme.
Having completed this module, you should be able to:
- Perform database backups using operating system commands
- Describe the recovery implications of closed and open database backups
- Perform closed and open database backups
- Identify the different types of control file backups
- Identify the backup implications of the logging and nologging options
- Describe backup issues associated with read-only tablespaces
This module introduced you to the following terms:
- Database Writer: The Database Writer is responsible for writing modified blocks from the database buffer cache back to the database files.
- System change number: System change number is a clock value for the Oracle database that describes a committed version of the database. It functions as a timestamp that helps to ensure transaction consistency.
- Media failure: Media failure refers to the error that occurs when you try to write or read a file that is required to operate the database. It is also called disk failure because there is a physical problem reading or writing physical files on the disk. Mirrored online redo logs: A mirrored online redo log is also called a multiplexed online redo log. It contains copies of online redo log files physically located on a separate disk. Any changes made to one member of the group are recorded in other members.
- Operating system backup: An operating system (O/S) backup is made using an operating system command. Operating system backups can be written to disk or tape in any format that a specific operating system supports.
- Control file: A control file is a binary file containing the name and creation time of the database, the names and locations of a database's datafiles and redo log files. Every time an instance of the database is started, its control file is used to identify the datafile and redo log file that must be open for the database to run properly.
In the next module, you will learn how to recover a database in NOARCHIVE mode in case of media failure.