Configuring iSCSI Storage for High Availability

Applies To: Microsoft iSCSI Software Target

You can configure failover clustering to provide high availability for the iSCSI storage that is provided by Windows Storage Server 2008 R2 or Windows Server 2008 R2.

Configuring failover clustering for Microsoft iSCSI Software Target 3.3

Before you configure Microsoft iSCSI Software Target 3.3 in a failover cluster, verify that you have the following configuration:

  • Microsoft iSCSI Software Target 3.3 is installed on each storage appliance running Windows Storage Server 2008 R2 or Windows Server 2008 R2 that will become a node in the failover cluster.

  • There are no iSCSI targets on the storage appliances running Windows Storage Server 2008 R2 or Windows Server 2008 R2 before the failover cluster is created.

  • Each storage appliance that will participate in the failover cluster passes all cluster validation tests in the Failover Cluster Management console.

  • The Failover Cluster feature is installed on each storage appliance and is configured to use a shared storage back-end such as iSCSI, fiber channel, or SAS interconnect.

  • There is at least one cluster disk listed in Available Storage in the Failover Cluster Management console.

  • The network adapters are configured to support separate subnets for storage and client access.

The following table contains a sample configuration of the network adapters that might be used. The example information is based on a storage appliance with three network interfaces.

Network Subnet IP address Allow clients to connect through this network Register connection in DNS
















A minimum of two networks are required for communication between nodes. Network interfaces can be configured with or without default gateways. For example, one network may be configured with a default gateway for client access and one network configured without a default gateway for communications between nodes.

The network properties for a failover cluster can be set through the Failover Cluster Management console. Because the subnet that is used for iSCSI storage is statically assigned and typically does not have a domain controller, DNS, or DHCP, that interface should be assigned a static IP address.

To ensure prompt performance when transferring resources between the nodes of a failover cluster, the Register this connection in DNS setting in the Advanced Properties of the interface’s IPv4 settings should be unchecked. For more information, see Configuring a Cluster Network for Performance.

To create a resource group

  1. To open Failover Cluster Management, click Start, point to Administrative Tools, and then click Failover Cluster Management.

  2. Expand the node for the cluster where you want to create the resource group.

    Right-click Services and Applications, click Configure a Service or Application, and then click Next.

  3. Under Select the service or application that you want to configure for high availability, click Other Server, and then click Next.

  4. In Name, type the name that clients will use to connect to this application. Resource group names must be unique on the failover cluster.

    For the statically assigned IP addresses in your cluster, you are prompted to define the address. Under Address, click the text box and enter the static address to use. If the network interface will not be used by clients to access the clustered application, clear the check box beside the network. Click Next.


If you previously created an iSCSI resource group, deleted it, and you are now unable to create it because of a name conflict, remove the name entry for the resource group in your designated DNS server.

  1. On the Select Storage page, select the disks to be assigned to this resource group. You can add additional disks at any time after the wizard is complete. Click Next.

  2. On the Select Resource Types page, do not select either option. Microsoft iSCSI Software Target 3.3 will automatically remove these resource types when they are created from this page. You should always use the Microsoft iSCSI Software Target console to create these resources.

  3. Review the information that is presented on the Confirmation page. If everything appears correctly, click Next.

  4. Review the report for the results, and then click Finish to exit the wizard.

To properly configure your network to support Microsoft iSCSI Software Target on your cluster, use the Failover Cluster Management console to delete any networks that are not required for iSCSI access. In the previous sample configuration, there would be a network listed in your resource group for the public subnet (192.168.1.x/24). This network address will not be used to connect to the Microsoft iSCSI Software Target resource on your failover cluster, and it should be removed.

Next, use the Microsoft iSCSI Software Target console to create an iSCSI target for the failover cluster. Make sure that you perform this procedure from the cluster node where the iSCSI resource group is currently active, otherwise you will be unable to modify the configuration.

To create an iSCSI target

  1. Expand Microsoft iSCSI Software Target, right-click iSCSI Targets, click Create iSCSI Target, and then click Next.

  2. In iSCSI target name, type a name to identify the iSCSI target. This could be the cluster name. In Description, type a short description of the target.

  3. In IQN Identifier, type the IQN for the iSCSI initiator that will connect to this target. You can also use the host name or IP address by clicking Advanced and choosing the appropriate type of address. Click Next.

  4. In Resource group, select the resource group to use for this target. If there are no initiators configured yet, you can use a random placeholder IQN, such as iqn.temp. Click Next.

  5. Click Finish.

After you have created the iSCSI target, you need to create a virtual disk to provide storage.

To create a virtual disk for an iSCSI target

  1. Open the Microsoft iSCSI Software Target console. Click Start, point to Administrative Tools, and then click Microsoft iSCSI Software Target.

  2. Expand iSCSI Targets. Right-click the target that you created in the previous steps, click Create Virtual Disk for iSCSI Target, and then click Next.

  3. Type the path and name for the virtual disk file, including the .vhd extension, such as C:\disks\data.vhd. Click Next.

  4. Type the size of the virtual disk in megabytes (MB), and then click Next.

  5. In Virtual disk description, type a short description for the disk, and then click Next.

  6. Click Finish.

Connecting iSCSI initiators

After you configure Microsoft iSCSI Software Target for high availability on your failover cluster and create the target and virtual disk, you need to connect your iSCSI initiators to the failover cluster resource.

To connect an iSCSI initiator to a computer running Windows Server 2008 R2

  1. To open the iSCSI Initiator Properties, click Start, click Control Panel, and then double-click iSCSI Initiator. Click Continue when you are prompted for User Account Control authorization. Click Yes to start the iSCSI service. Click Yes to automatically open the Windows Firewall ports for the iSCSI Service.

  2. On the Discovery tab under Target portals, click Add Portal. Enter the DNS name or the IP address of the cluster storage appliance.

  3. Click the Targets tab.

  4. Select the target to connect to, and then click Log on. If the desired target does not appear in the list, click Refresh.

  5. Select Automatically restore this connection when the computer starts, and then click OK.


If your storage appliance supports Microsoft Multipath I/O (MPIO) select Enable multi-path. Only use this option if MPIO software is installed on your storage appliance.

  1. Click OK to save the settings. Repeat these steps on the other cluster storage appliance.

Additional considerations

  • You must be a member of the local Administrators group to perform these tasks.

  • To open iSCSI Software Target, click Start, point to Administrative Tools, and then click Microsoft iSCSI Software Target. (Another way to open iSCSI Software Target is to click Start, click Run, and then type iscsitarget.msc.)

  • To open Failover Cluster Management, click Start, point to Administrative Tools, and then click Failover Cluster Management.

  • After configuring the cluster environment for failover clustering, use the information in iSCSI Software Target Help to set up iSCSI targets, iSCSI virtual disks, and other items.

Additional references

Microsoft iSCSI Software Target 3.3

Failover Clusters