Cannot add 2nd Hdd with same file path on 2nd Server 2012 for Exchange DAG

Hi,

I have 4 servers, 2 with the CAS role installed and 2 with the mailbox role installed, all under Server 2012.

I set up a DAG and added both MBX Servers.

On the first MBX Server I added a vdisk, labeled it "F". On the second MBX Server I cannot add a drive with the same letter.

What am I missing?

Kr´s