When operating Oracle Database in NOARCHIVELOG mode, you can still restore your database to the exact point in time when a backup was taken, as long as you regularly create backups using RMAN.
This article explains, step-by-step and with diagrams, how to restore an Oracle database to the backup point using RMAN in a NOARCHIVELOG environment (i.e., without archived redo logs).
📌 What Is NOARCHIVELOG Mode?
Let’s briefly compare NOARCHIVELOG mode and ARCHIVELOG mode to clarify their behavior.
┌──────────────────────────────┐
│ Log Output Modes │
├────────────────┬────────────────────┤
│ NOARCHIVELOG │ Redo logs are not archived (overwritten) │
│ ARCHIVELOG │ Redo logs are archived and preserved │
└────────────────┴────────────────────┘
In NOARCHIVELOG mode, complete recovery is not possible.
Instead, RMAN allows you to restore the database to the exact state it was in when the backup was taken.
✅ Preconditions
| Item | Requirement |
|---|---|
| Database mode | NOARCHIVELOG |
| RMAN backup | A full RMAN backup was taken prior to failure |
| Backup storage | The backup is stored in FRA or a designated location |
| Archive logs / redo | Not used (no archived logs generated) |
🧭 Recovery Flow Overview
┌────────────────────────────────────┐
│ Restore Procedure (NOARCHIVELOG) │
├────────────────────┬───────────────────┤
│ ① Connect to RMAN │ Connect to the target database │
│ ② Startup in MOUNT mode │ Do not OPEN yet │
│ ③ RESTORE │ Restore from backup │
│ ④ RECOVER │ Apply available redo (limited) │
│ ⑤ OPEN RESETLOGS │ Open the DB at the backup point │
└────────────────────┴───────────────────┘
⚠️ Note: Any data added or changed after the backup will be lost.
🛠️ Step-by-Step Commands
① Connect to RMAN
$ rman target /
② Start the Database in MOUNT Mode
STARTUP MOUNT;
You must keep the database in MOUNT mode because you will restore files before opening the database.
③ Restore the Database from Backup
RESTORE DATABASE;
This restores datafiles and control files from the previously created backup.
④ Perform Basic Recovery (Redo Only)
RECOVER DATABASE;
Since NOARCHIVELOG mode doesn’t generate archive logs, only redo still present in the redo logs can be applied.
⑤ Open the Database with RESETLOGS
ALTER DATABASE OPEN RESETLOGS;
This command reinitializes redo logs and opens the database in a consistent state as of the backup time.
⚠️ Important Considerations
| Item | Note |
|---|---|
| Archive logs | Not used. Cannot recover beyond backup time |
| Online backup restrictions | Online backups are not allowed in NOARCHIVELOG mode |
| RESETLOGS required | Must open the database with RESETLOGS after restore |
📘 Best Practices for NOARCHIVELOG Mode
NOARCHIVELOG mode is usually suitable for development or testing environments. If used in production, take the following precautions:
┌────────────────────────────────────┐
│ Safe Operation Tips (NOARCHIVELOG) │
├────────────────────────────────────┤
│ ✔ Stop the DB regularly to take backups │
│ ✔ Use large redo logs to avoid quick overwriting │
│ ✔ Automate nightly backups using RMAN scripts │
└────────────────────────────────────┘
✅ Summary: You Can Restore with RMAN Even Without Archive Logs
Even in NOARCHIVELOG mode, if you’ve taken a valid RMAN backup, you can restore your database to that exact point.
┌──────────────────────────────────────────┐
│ Key Benefits of RMAN in NOARCHIVELOG Mode │
├──────────────────────────────────────────┤
│ ✔ Restores the database exactly to backup time │
│ ✔ Enables recovery even in failure scenarios │
│ ✔ Simple to manage and automate │
└──────────────────────────────────────────┘
However, remember that NOARCHIVELOG mode carries a high risk of data loss.
For mission-critical systems, switching to ARCHIVELOG mode is strongly recommended.
[reference]
9.2.2 RMAN Repository
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