Correct way to backup remote drives on a Microsoft Cluster

Hi,

I backup Databases hosted on a Microsoft CLuster 

I created the Microsoft pseudo client and add a SQL instance on it.

I also backup each Microsoft node through the filesystem agent.

I have enabled System state on each node.

The default subclient backup only the C and local drives.

I created another subclient on each node, but I can specify the disks presented by storage only on the active node.

What is the correct way to backup the remote disks present on the Active node.

Those disks are presented by a Storage and have their letters R,S,T

If a failover occurs, those disk are owned by the remaining node.

I tried to add a subclient at FIle System agent on the cluster it self, but it backups only the quorum disk and it gaves an error message.

Thanks for your help !