HI @Daniel Brouwer 

Let me help you with that query

When a metadata drive in a HyperScale storage pool fails due to disk issues, it can be replaced with a new empty disk that is the same size. Metadata drive is the drive containing the Index Cache and/or the deduplicated database (DDB). 

To do so, please follow these instructions:

1. Shut down the node and remove the defective disk containing the metadata. 

2. Attach the new replacement disk to the MediaAgent that has the failed disk. 

3. Reboot the node. 

4. Note: Do not mount the disk on the MediaAgent after the reboot. 

5. Navigate to the following folder: 

           /opt/commvault/Base/ 

6. Run the following command: 

          ./CVSDS -m -l /dev/<new disk> 

          For example: 

          ./CVSDS -m -l /dev/sdf 

7. To replace multiple disks, include all the names in the <new disk> list, using a comma (,) as the delimiter. 

          For example: 

         ./CVSDS -m -l /dev/,/dev/sdf 

The following prompt will be displayed: 

Please confirm whether node has been rebooted after the metadata drive has been replaced by/n]: 

Type y and press Enter. 

The command will mount the drive, and the Index Cache and/or the deduplicated database (DDB) will be automatically reconstructed in the new disk, if it is a control node.  

Once the reconstruction of the DDB is completed the metadrive will be ready for Deduplicated operations. 

If that answers your question, feel free to mark this post as the correct answer.

Thank you