Re: Backup of Oracle databases

simon_at_openplus.co.uk (Simon Fawkes) writes:

>I need some information about backing up Oracle databases. I want to
>perform a file level backup of an oracle database whilst the database
>is running. Whilst this backup is being performed there will be no
>updates. Is there anyway of locking the database so no updates can be
>performed but reads are still allowed. If there is is this a safe way
>of performing the backup.
 

>TIA
 
>Simon Fawkes

Simon,

The safest way to allow the database to be available for reads during a backup is to perform a "hot backup" of the database. Not only can the users read data, they can update, insert, and basically do everything they normally can do. During that period, all database files can be backed up to tape.

A discussion of hot backups is beyond the scope of a posting - several books contain descriptions on how to do this. My favorite is "ORACLE Backup and Recovery Handbook" by Oracle Press.

Another option you might want to think about is exporting the database while it is up. Simply use the "consistent=y" option. Remember, however, that exports cannot recover to a point-in-time after the export, while image backups can recover to the point of a crash.

Hope this helps!

-Ari Kaplan
Independent Oracle DBA Consultant

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