Release date: December 24, 2021
Bulletin ID: TEC-202112-01
Severity rating: Critical

Affected Products

QNAP x86-based NAS models using SSD Cache and running the following QTS 5.0.0 versions:

• QTS 5.0.0.1716 Build 20210701 (Public Beta) 
• QTS 5.0.0.1785 Build 20210908 (Release Candidate)
• QTS 5.0.0.1808 Build 20211001
• QTS 5.0.0.1828 Build 20211020 
• QTS 5.0.0.1837 Build 20211029 
• QTS 5.0.0.1850 build 20211111 
• QTS 5.0.0.1853 build 20211114 
• QTS 5.0.0.1858 build 20211119 
• QTS 5.0.0.1870 build 20211201 

Note
All QuTS hero versions, which adopt a different file system (ZFS), are not affected by these issues.

Summary

On certain NAS devices, the new SSD cache technology implemented in QTS 5.0.0 may cause data corruption and the following errors:

• Unable to mount volumes
• Unable to perform input/output operations
• Unable to access certain files

Our investigation shows that data corruption issues mainly occur in the following SSD cache use cases:

• SSD cache usage is over 2TB.
• The NAS performs intensive input/output operations.

These issues may also occasionally occur in the following uses cases:

• Users have disabled or removed SSD cache.
• Users have restarted the NAS after creating SSD cache.  

We have fixed all identified issues in the QTS update released on December 24, 2021. Whether your device is affected or not, we strongly recommend updating your firmware to QTS 5.0.0.1891 (or later versions). You can refer to our FAQs to learn more about these issues.

Solution

If your NAS is using SSD cache and running one of the earlier QTS 5.0.0 versions, and if you discover the above-mentioned errors on your device, we recommend following the below procedure to keep important snapshots, avoid worsening the current situation, and allow our Technical Support to provide more effective assistance if needed.

Important: DO NOT run a file system check in Storage & Snapshots.  

Recommended Procedure

1. Keep the current SSD cache settings.
2. Disable the current snapshot schedules.
   Note: Disabling snapshot schedules prevents recycling older snapshots that can be used to restore an earlier environment unaffected by the issues.
3. Keep existing snapshots permanently. 
4. Update QTS to the latest version.
5. Recover data.
• If you have taken snapshots:
• Choose an appropriate data recovery option according to your needs. For details, see the QTS Help.
• If you have used other backup methods:
• Create a volume . For details, see the QTS Help.
• Move your backup data to this new volume.
6. Contact QNAP Technical Support for further assistance if necessary.

Tip: You can enable snapshot schedules again when your system and data are back to normal.  

Disabling Snapshot Schedules & Keeping Snapshots Permanently

1. Log in to QTS as administrator.
2. Go to Storage & Snapshots > Storage/Snapshots.
3. Select a volume, click Snapshot, and select Snapshot Manager.
4. Click Schedule Snapshot.
5. Disable the schedule and click OK.
6. Select a snapshot and then click Edit.
7. Select Keep this snapshot permanently and then click OK.
8. Follow the same steps for other volumes and snapshots.

Updating QTS to the Latest Version

1. Log in to QTS as administrator.
2. Go to Control Panel > System > Firmware Update.
3. Under Live Update, click Check for Update.
   QTS downloads and installs the latest available update.

Tip: You can also download the latest update from the QNAP Website > Support > Download > OS & Firmware Update. Upload the file to Control Panel > System > Firmware Update and then perform a manual update.

Revision History
V 1.0 (December 24, 2021)  - Published