Steps to perform Open Database Backups using Oracle
SVRMGR30 at the prompt to connect to Server Manager and press Enter.
CONNECT INTERNAL to access the database as sysdba and press Enter.
ORACLE as the password and press Enter.
- Now determine if the database is running in the correct mode (ARCHIVELOG or NOARCHIVELOG) by typing
ARCHIVE LOG LIST at the prompt. When you finish, press Enter.
- Select columns FILE_NAME and TABLESPACE_NAME (in this sequence) from the data dictionary view that contains this information. Type
SELECT FILE_NAME, TABLESPACE_NAME FROM DBA_DATA_FILES; at the prompt. After you finish, press Enter.
- Now type
ALTER TABLESPACE SYSTEM BEGIN BACKUP; at the prompt. After you finish, press Enter.
- While maintaining your Server Manager session, get an Operating System prompt in order to perform your backup. Type
HOST at the prompt and press Enter.
- Copy the file c:\ORANT\DATABASE\SYS1ORCL.ORA to the current directory by typing COPY
C:\ORANT\DATABASE\SYS1ORCL.ORA. After you finish, press Enter.
- Now check whether the backup is successful. Type
DIR at the prompt and press Enter.
- Now return to your Server Manager session. Type
EXIT at the prompt and press Enter.
- Now end the backup. Type
ALTER TABLESPACE SYSTEM END BACKUP; at the prompt and press Enter.
- This is the end of the simulation.
Consistent and Inconsistent Backups
A backup is either consistent or inconsistent. To make a consistent backup, your database must have been shut down cleanly and remain closed for the duration of the backup. All committed changes are written to the data files during the shut down process, so the data files are in a transaction-consistent state. When you restore your data files from a consistent backup, you can open the database immediately.
If the database is in ARCHIVELOG mode, then you can make inconsistent backups that are recoverable using archived redo log files. Open database backups are inconsistent because the online redo log files contain changes not yet applied to the data files. The online redo log files must be archived and then backed up with the data files to ensure recoverability.
Despite the name, an inconsistent backup is as robust a form of backup as a consistent backup. The advantage of making inconsistent backups is that you can back up your database while the database is open for updates.