I'm dealing with a problem whereby a I have a database that is managed using data guard using Redo Apply, so redo logs are copied to the target database, applied and kept in sync ready for fail over.

The target (DR) database has been offline for a while, and upon investigating found to be offline, and unable to start due to control file missing.

The original database was an exact copy, so relative file paths and name consistent with the primary database.

I have a few ideas on sorting this and wondered whether anyone can offer some experience.

1) Copy the missing control file from primary to DR server and try to start up. I'm guessing over time additional files may have been added to primary which may not be in the DR. I'm also concerned about messing up what could currently be recovered?

2) Export the current primary control file to trace > sql, and modifying to fit target database, then creating the control file using sql

3) Start again, create a new DR target.. Having not created the initial DR (data guard) setup I'm not entirely sure of how easy this is, but I know it would work at least.

Any advice welcome TIA


You should have more than one copy of controlfile on each side. On primary use:


This will create a copy on controlfile, where special flag is set. This will allow database to apply redologs which are both newer/older than controlfile's SCN.

  • thanks! ok, so just tried that. I get an error saying "control file is for a standby database". Now I'd assume that's how it would have been setup, but would data guard work with a target database that isn't a standby? – sambomartin Oct 12 '15 at 12:09
  • I've found another control file on the target (apparently not standby) is it worth changing param file or copying and renaming the control file? – sambomartin Oct 12 '15 at 12:11
  • now to get it sync'd – sambomartin Oct 12 '15 at 12:16

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