Configuring iSCSI MPIO on Windows Server 2016 requires the following steps:
- Enable the iSCSI Initiator Service.
- Enable the MPIO feature - this procedure is required only once per Server;
- Add multiple sessions to a VPSA iSCSI target - this procedure is required to be executed once for every VPSA the Server is connected to.
- Setting up and accessing the VPSA Block Volume in Windows
- Adjusting DSM and Disk timeout settings
1. Enable the iSCSI Initiator Service
In the Windows Search box type iSCSI and then select the Desktop app: 
If this is a clean Windows installation, or the iSCSI service has never been enabled before, you will be prompted to start the service, select Yes:
You will then be presented with the iSCSI Initiator Properties window:
The key piece of information we need from here is the Initiator Name under the Configuration tab (this will be required in Step 3):
2. Enable the MPIO Feature on Windows 2016 Server
MPIO is a Feature in Server 2016 listed as 'Multipath I/O'. It should be enabled as follows:
Open Server Manager and under Manage select Add Roles and Features:
Select Role/Feature-based installation, then Next:
Select the relevant server from the list, then Next:
On the Features screen select Multipath I/O, then Next:
Select the tick the box to Restart the Server automatically (optional), then click Install (and reboot later if 'restart automatically' was not selected):
Once the server has rebooted, go to Control Panel and select MPIO:
On the MPIO Devices tab click on the Discover Multi-Paths tab and check the box for Add support for iSCSI devices. Click Add and then Yes to reboot.
Note: In some cases the "Add support for iSCSI devices” check-box is grayed out. To enable it, you need to first connect the Server to the VPSA (follow the steps for Adding a [Windows] Server to a VPSA), attach a Volume from the VPSA to this Server and then return to this step.
After rebooting, open the MPIO Properties Control Panel applet again and you should see the iSCSI bus listed as a device:
2. Discover and Connect to the VPSA Target Portal
1. Log in to the VPSA GUI.
2. In the Servers pane, select Add then Manual:
3. Enter a Name for the Server. Toggle File Access to OFF. Toggle iSCSI to ON, then copy the Windows Server iSCSI Initiator Name (identified at the end of Step 1) and paste it in the IQN field that appears. Click on Edit, then enter a User and Secret (unless you want to use the defaults). Finally, click Create:
4. Go to Server Manager - Tools - iSCSI Initiator:
5. On the VPSA GUI Controllers tab, identify the iSCSI IP of the VPSA. Go to the iSCSI Initiator Properties window and enter this IP address into the Target box on the Targets tab. Click Quick Connect... then click Done on the Quick Connect box that appears:
6. The VPSA's IQN should now appear with a status of Inactive:
7. Next, click on Connect. On the Connect To Target window tick Enable multi-path then click Advanced...
On the Advanced Settings window set the following:
- Local adapter - Microsoft iSCSI Initiator
- Initiator IP - the IP address of NIC #1
- Target Portal IP - IP address of the VPSA
- Enable CHAP log on - tick the box
- Name - VPSA Server CHAP User set in Step 3
- Target secret - VPSA Server CHAP Secret set in Step 3
Select OK, then OK again.
8. The status of the Target will now indicate Connected:
9. Repeat Step 7 to add the 2nd NIC IP address in Advanced Settings - Initiator IP. All other settings will be the same.
10. On the iSCSI Initiator Properties window click Properties and you will see 2 sessions:
11. Looking in the VPSA GUI we will see 2 sessions for this Server:
12. While in the VPSA GUI, attach a Volume to the Server:
13. Once a Volume has been attached to the Server, go back to the iSCSI Initiator Properties window, select Devices... then MPIO... where we can now see the 2 sessions/devices and the Load balance policy:
14. If additional iSCSI sessions are required, to provide additional bandwidth, repeat Steps 7 & 9 to add NIC#1 and NIC#2 Initiator IPs again.
E.g. with 4 sessions (2 sessions per NIC):
4. Accessing the VPSA Block Volume on the Windows Server
To access the Block Volume on the VPSA the Disk will first need to be brought online. It will then need to be initialized and formatted. Follow the steps below to complete the setup process and make the Volume accessible in Windows.
Go to Disk Management, identify the newly available Volume, right-click to the left of the white space and select Online. Then repeat and select Initialize Disk and work through the subsequent pages that are displayed:
Right-click in the white space and select New Simple Volume:
The Volume will now be visible in Windows Explorer:
5. Adjusting DSM and Disk timeout settings
In order to accommodate for VPSA maintenance (e.g. VPSA failover), it is necessary to reconfigure the DSM timer counters as follows:
1. In Windows Explorer, right-click the newly added Volume / Drive (e.g. F:\ drive) and select Properties.
2. Click on the Hardware tab.
3. Click on the Zadara VPSA Multi-Path Disk Device and then Properties.
4. Next to DSM Name click on Details.
5. Set the following:
- Path Verify period = 20
- Path Verify Enabled = ticked
- Retry count = 6
- Retry interval = 1
- PDO Remove Period = 30
6. Click OK three times to come out. A reboot will be required for these settings to take effect, but first we need to change one more setting.
7. Open regedit and browse to the following key:
- HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Disk\TimeOutValue
8. Change the value of TimeOutValue to 120 (decimal)
9. Close regedit and reboot the Server. Everything is now configured.
