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

✅ Answer (Real-Time DBA Explanation)

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.