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How to create a Windows Server 2012 R2 failover cluster using QNAP Virtualization Station (server nodes) and NAS iSCSI targets (shared storages)?

This tutorial describes how to use virtual machines (VMs) which are installed in Windows Server 2012 R2 as nodes for Windows Failover Cluster. By using QNAP Virtualization Station, creating a VM as a node of a cluster, you can easy to build a failover clustering and protect mission-critical applications running on Windows Server 2012 R2. For instance, if you have an AD server in your IT environment, the QNAP NAS allows you to create a VM as a backup server. When the AD server is down, the VM can take over the service throughout the Windows failover clustering.

Please note: a shared storage is necessary for creating a Windows Server 2012 failover cluster so we are going to use NAS iSCSI targets as shared storage in this tutorial.


What is a failover cluster?
It is a group of servers (physical or virtualized) that can maintain high availability of applications and services. A server can be seen as a node of a cluster. If one of the servers fails, another server (node) in the cluster can take over its workload and ensure critical application services will not be interrupted, and to minimize downtime. This mechanism is known as failover. (Rouse 2012)


  • Windows Server 2012 R2 VM is installed in the Virtualization Station and similar configurations with your product server. As shown below, the selected orange area displays the Windows Server VM installed in the QNAP NAS and uses the Virtual Switch to connect the network interfaces. (More information about Virtual Switches.)
  • An additional network connection is required to connect two Windows Servers in the cluster and the NAS shared storage. The yellow connection below is used to communicate each node of the cluster; while a blue one connects the nodes to the NAS shared storage.

NAS Settings

  1. Create iSCSI Storage
    For shared storage, we are using the iSCSI storage of NAS for the failover clustering. There are two iSCSI storage should be added, with “Quorum” and “Data”. The quorum is used to determine if the cluster has stopped running if the number of nodes drops below the majority, which is the minimal number of nodes of a cluster. In a simple action, the quorum will tell the cluster which node should be active at any given time, and intervenes if communication fails between the nodes (Microsoft 2011). On the other hand, Data is a normal shared storage for the nodes used.

    The minimal requirement for the Quorum is 512 MB (we will use 1GB in the tutorial), while there is no limited capacity for the Data volume and it depends on your needs.
    For a more detailed demonstration, please refer to How to link iSCSI targets to VMs of Virtualization Station

Virtualization Station Settings

  1. Install Windows Server 2012 R2
    Upload the Windows Server 2012 R2 ISO image to the NAS. In Virtualization Station, go to Create VM > Create Custom VM. You can specify the VM resources including CPU cores, memory and storage capacity. For more information about creating a VM, please click here.
  2. Configure the VM Network Settings
    Due to the demands of shared storage, we need an additional Virtual Switch to connect a NAS Ethernet interface which is connected to the network where the shared storage is. Go to Network Setting > Add Virtual Switch”. There are three different networking modes, and select “Set up as Bridged Networking”. Select the interface which can access the shared storage and click Create. For instance, the Ethernet interface of NAS shown on the above illustration is and the shared storage is also in the same subnet (172.17.100.xxx). For more information regarding networking modes, please click here.
  3. Add a virtual network interface controller (NIC) for the VM to connect to the shared storage.
    The virtual NIC of the VM should be attached to the Virtual Switch in which the network can access the shared storage. Click the VM on the main menu > Virtual Machine Settings > Add Device, and select the Virtual Switch 2 which we added in the previous step.

  4. Add the VM to the Domain
    The domain controller server is needed for creating the failover clustering so you need to add the VM in the domain.
    Click Start, right click on “This PC”, go to Properties > Change settings > Change, and choose “Domain” then insert the domain name.

    Please note: in some cases, you may need to manually set the DNS before your server is added to the domain. Click Start > Control Panel > Network and Internet > Network and Sharing Center.

    Click Ethernet > Properties > Internet Protocol Version 4 (TCP/IPv4), and choose “Use the following DNS server addresses:” then enter the IP address of the DNS server.
  5. Install Failover Clustering
    For being a node of cluster, the server should first have the Failover Clustering feature installed. Click “Add roles and features” then click Next.

    Choose “Role-based or feature-based installation and click Next.

    Click Next.

    Click Next.

    Select “Failover Clustering” and click “Add Features”.

    Click Next.

    Click “Install” then click “Close” when the installation is finished.

  6. Connect to the NAS iSCSI storage
    The iSCSI targets, Quorum and Data, should be added.
    Click “Tools” and choose “iSCSI Initiator”.

    Choose “Discovery” and click “Discover Portal...”. Enter the NAS IP address (e.g. and click “OK”. Go back to “Targets”, and two iSCSI targets will be inactive. Select them and click “Connect”. When they are connected, click “OK”.
    Right click on “Start” and select “Disk Management”. The Quorum and Data iSCSI targets will be listed.

    Right click on the disk, select “Online”, and then click “OK”.

    Right click on the disk and choose “New Simple Volume…”. Then configure the volume settings. For further steps, please click here.

    Please repeat step 6 on your Windows Server 2012 R2. Instead of formatting the disks (Quorum and Data) again, you just need to make them online.

Setup Failover Clustering

  1. Install the Failover Cluster Manager
    After preparing the NAS VM, you have two Windows Servers in the same domain and sharing the NAS storage. We have to prepare another Windows Server to install the Failover Clustering Manager.

    Before installing the Failover Cluster Manager, the Failover Clustering feature must first be installed. Please refer to step 5 of NAS Settings.

    Click “Tools” and select “Failover Cluster Manager” in the Server Manager.
  2. Validate the Failover Clustering
    Click “Validate Configuration” and click “Next”.

    Enter the name of the servers.

    Select “Run all tests (recommended)” and click “Next”.

    Check both Cluster Disks (Quorum and Data) and click “Next”.

    After validating the failover clustering, the system will provide a report including all parameter checks.

    Choose “Nodes” in the category and you can observe the status of the Windows Servers.

Rouse, M. (2012). failover cluster definition. Available:
http://searchwindowsserver.techtarget.com/definition/failover-cluster. Last accessed 21st Sept 2015.
Microsoft. (2011). Understanding Quorum Configurations in a Failover Cluster. Available:
https://technet.microsoft.com/en-us/library/cc731739.aspx. Last accessed 23rd Sept 2015.

Release date: 2015-11-23
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