Q1. In production, what happens if the CONTROL FILE is missing during database startup?

Answer.

The control file is the most critical file required for Oracle database startup.
If it is missing or corrupted:

• Database cannot move beyond MOUNT stage
• Oracle cannot locate:
  • Datafiles
  • Redo logs
  • Checkpoint information

Error Seen:

ORA-00205: error in identifying control file

ORA-00210: cannot open the specified control file

Production Fix:

1. Restore control file from backup:

RESTORE CONTROLFILE FROM AUTOBACKUP;

1. If multiplexed control files exist, copy from healthy member.

Best Practice:

• Always keep 3 multiplexed control files on separate disks.