[Backup and recovery] recover data files in noarchivelog Mode

Cause:

The data file in noarchivelog mode is corrupted.

Solution:

Method 1 (non-RMAN backup ):

Because there are no archived log files, the restoration operation cannot be performed in noarchivelog mode and can only be completed. Because no log files are archived to synchronize the restored data files with the rest of the database, the database cannot be opened. Therefore, the only option in noarchivelog mode is to restore the entire database (including all data files and control files ). After all files are restored from a complete offline backup, these files are synchronized in the database after the restoration, so that the database can be opened.

Disadvantage: All work after this backup will be lost.

Method 2 (RMAN backup ):

Because RMAN does not back up online redo log files, the database will still lose these files after the complete restoration operation is performed. For this reason, the restored Startup operation will fail and the database will stop in the loading mode. Because it is in loading mode, you can run the alter database clear logfile group <group number> command to recreate all log file groups. Then, the database is opened.

Disadvantage: All work after this backup will be lost.