Oracle-L: RE: Opinions on B&R scenarios

From: Fink, Dan <Dan.Fink_at_mdx.com>
Date: Wed, 23 Oct 2002 08:14:08 -0800
Message-ID: <F001.004F1198.20021023081408@fatcity.com>

Rick,

	I will assume that all logs are properly backed up.
	The only difference in the recoverability of the 2 scenarios is that

an incomplete recovery cannot be done to a time while any tablespace in the database is in hot backup mode. So, there is a window of exposure in Scenario 1, that does not exist in 2. For this reason, it is recommended that each tablespace be placed in backup mode, the files copied, the tablespace taken out of backup mode and the process sleeps for 1 minute. Repeat with the next tablespace, etc.

In terms of backup, Scenario 2 is simpler to implement. But it also requires downtime. If the backup process fails, the database is probably down. In Scenario 1, if the backup process fails, the database is still up (but may need some assistance to return to normal operations).

To answer your question directly, your co-worker is correct (given the assumption stated above). If the database is taken down in a consistent mode, technically speaking you don't need the redo logs. However, it will complicate the recovery.

Dan Fink

-----Original Message-----
Sent: Wednesday, October 23, 2002 9:15 AM To: Multiple recipients of list ORACLE-L

Hi DBAs,

A co-worker and I disagree on impact of slightly different B&R scenarios and I would like your thoughts.

Environment for both scenarios: Oracle 8.1.6, WinNt, Archivelog mode, not using RMAN

Scenario 1:

       I do standard Hot Backup using
     BEGIN BACKUP
          OCOPY ...
     END BACKUP
                .....

        If database crashes I perform media recovery then recover database.

Scenario 2:
     Co-worker shuts down database and copy all files to backup directory.
     Restarts database backup
                If database crashes restore backup files then apply the

archive logs.

Co-worker says both scenarios are the same. I think scenario 1 results in no loss where scenario 2 results in the loss of data that was in the online redo logs.

Any thoughts on this?
Also what is the minimum system/object priviledges a user needs to perform B&R. I would like to create a user with only those privs necessary for B&R.

Thanks
Rick

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Author: Fink, Dan
INET: Dan.Fink_at_mdx.com

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