Failover Cluster & DFS on NAS SRV2012 R2

Dear all,

I've been searching for NAS solution to configure Failover Clustering and DFS.. There are too many scenarios as well definitions, and I need a best practices..

Shortly

I have 2 HP Servers each one has the following.

HP 8G

1. Domain Controller (Physically)
   
2. File Server (Hyper-v)
   
3. Exchange Server (Hyper-v)

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HP G6

1. Additional Domain Controller (Physically)
   
2. Additional File Server (Hyper-v)
3. Additional Exchange Server (Hyper-v)

I believe that I can configure the Failover Clusters on the servers it self..?!

But i need to configure the files server DFS to be placed on the NAS, but I'm not sure about the NAS compatibility with 2012 R2 e.g (WD DX4000, QNAP, DELL..) and also whether this is a right figure.. So please can anyone help me?