Posts Tagged ‘controlfile’


So That’s What Those Hidden Oracle Parameters Are For!

November 5th, 2008 by Robert McMillen • No Comments »
We hit this issue when we were cloning a production RAC environment that had been backed up using RMAN and then restored to a non-RAC test environment. To get past it, we had to add a hidden parameter to the target init.ora file to allow us to open the duplicated database, and then remove it once the database was opened.

The solution turned out to be:

Set the following parameter in the auxiliary init.ora file:

_no_recovery_through_resetlogs=TRUE

Then open with resetlogs;

Once the auxiliary has opened, removed this hidden parameter.

This problem comes from unpublished Bug 4355382 ORA-38856: FAILED TO OPEN DATABASE WITH RESETLOGS WHEN USING RAC BACKUP

According to Oracle Support:

ORA-38856 is the expected error during open database resetlogs when the set of enabled instances (redo threads) in the controlfile does not match the set of enabled instances (redo threads) in datafile checkpoint. This is expected behavior in a normal RAC restore/recover/open resetlogs situation.

However, in a cloning scenario where once the clone database is opened with resetlogs and you would never expect to restore the old (RAC) backup, this check doesn’t matter.

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