QNAP Check File System Volume Could Not Be Unmounted: Troubleshooting and Solution

When running a check file system on your QNAP NAS, you may encounter an issue where the volume cannot be unmounted. This can be frustrating, especially if you are trying to troubleshoot and resolve the problem quickly. In this article, we will discuss the common causes of this issue and provide a step-by-step solution to unmount the affected volumes.

Causes of the Issue

The most common cause of the 'Check File System volume could not be unmounted' error is when the system detects an issue with one or more of your storage pool's disks. This can happen due to various reasons such as disk corruption, hardware failure, or software issues. When this happens, the QNAP NAS will automatically put the affected volumes in 'Read Only' mode to prevent further data loss.

Symptoms and Diagnosis

The symptoms of this issue include:

* The system will display an error message stating that the volume cannot be unmounted.

* The 'Check File System' process will fail halfway through, citing a problem with unmounting disks.

* Your storage pool may become unavailable or inaccessible due to the affected volumes being in 'Read Only' mode.

Solution

To resolve this issue, you need to forcefully unmount the affected volumes using the Telnet or SSH command-line interface. Follow these steps:

1. Connect to your QNAP NAS via Telnet or SSH.

2. Run the following commands to list all the mounted volumes:

```

ls -l /share/CE_CACHEDEV1_DATA

```

3. Identify the volumes that are affected by this issue and note their mount points.

4. Run the 'lazy unmount' command to unmount each of the affected volumes, using the `-l` option:

```

umount -l /share/CE_CACHEDEV1_DATA/

```

Replace `` with the actual mount point of the affected volume.

5. Repeat step 4 for all the affected volumes.

6. After unmounting all the affected volumes, run a 'Check File System' again to ensure that the issue is resolved.

Additional Tips

* To avoid this issue in the future, make sure to regularly back up your data and monitor your storage pool's health.

* If you are using Cache Acceleration on your QNAP NAS, be aware that disabling it may cause linked volumes to become 'Read Only'.

* In some cases, you may need to disable the 'Cache Acceleration' feature altogether if you encounter issues with your SSD cache volume.

The 'Check File System volume could not be unmounted' error can be frustrating and time-consuming to resolve. However, by following the steps outlined in this article, you should be able to forcefully unmount the affected volumes and get your storage pool up and running again. Remember to regularly back up your data and monitor your storage pool's health to avoid encountering this issue in the future.

Qnap check file system volume could not be unmounted