How can I determine the cause of a dropped disk?

Last modified date: 2023-12-07

Applicable Products

All NAS series

Scenario

A disk on my NAS suddenly drops or goes offline (the system can no longer detect the disk). There was no warning or error.

After restarting the NAS or removing and installing the disk again, the disk may or may not be recovered, and may drop again.

How can I determine what is causing the disk to drop?

Best Practice

We recommend performing the following actions to help determine the cause of a dropped disk.

Important

Back up all data on the NAS before you start.

Ensure the disk is compatible with your NAS model by checking the Compatibility List.
If the disk model is not listed, unpredictable issues may occur when using the disk on your NAS.
Determine if the issue comes from the disk or the disk slot.
1. Power off the NAS.
2. Swap disk slots between the dropped disk and a healthy disk.
  For example, if the dropped disk is in slot 1, and a healthy disk is in slot 2, remove both disks and install the dropped disk in slot 2 and the healthy disk in slot 1.
  Warning
  Ensure the NAS is completely powered off before you swap the disks. If you swap the disks when the NAS is running, RAID settings and metadata can become corrupted and unrecoverable.
  Note
  QNAP NAS devices use software RAID. Even when the disk order is changed, the system can still reassemble the RAID group automatically.
3. Power on the NAS.
4. Observe which disk drops out of the system.
  Condition Description
  The dropped disk drops again. The disk is faulty.
  See step 3.
  The healthy disk drops. The disk slot is faulty.
  Return the NAS to QNAP or a QNAP-authorized service center for repair.
Use diagnostic software provided by the disk manufacturer for advanced testing.
1. Shut down the NAS.
2. Remove the problematic disk.
3. Connect the disk to a computer running the diagnostic software.
4. Follow the diagnostic software user guide provided by the disk manufacturer.
  Warning
  Do not perform any write operations on the disk. While most diagnostic tools only perform read operations, performing any write operations may cause RAID metadata on the disk to become corrupted and unrecoverable.

Further Reading

What should I do if the disk drops?

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