Hi, CaffeLake!
Please kindly share with us the below information:
The model and version of VCN.
1. Any alarms appeared?
2. Was it working fine before?
3. Can you show us the status of the hard disk as per the below picture?
4. Please run the following commands and send screenshots with the result:
a) Cli rginfolist;
b) Cli vdinfolist;
c) Cli pdinfolist.
Like this:

From the known information, this should be a hardware failure.
We may need remote assistance to determine the problem. Please submit a ticket and our engineers will help with the problem.