In this post, I will show you how to use the Windows Server iSCSI Initiator to create a network fault-tolerant connection to an iSCSI target by configuring MPIO. Note that the lab used for the below scenario was based on a Windows Server 2016 connecting to an Azure StorSimple 1200 virtual appliance.
Add two network interfaces to the server that will be connecting to the storage appliance. Each interface will connect to the iSCSI storage system. Various vendors will have requirements for the network configurations:
In my case, both iSCSI NICs are on different networks:
Each iSCSI NIC on the server will have 1 connection to a corresponding NIC on the storage appliance. This means that there will be 2 iSCSI sessions for each iSCSI volume on the storage appliance that the server will connect to.
If I used a single VLAN/subnet for all iSCSI traffic, each iSCSI NIC on the server could connect to both iSCSI NICs on the storage appliance. There are 2 sessions per iSCSI NIC per volume. This means that there would be 4 sessions per volume that the server will connect to.
Make sure that the two iSCSI interfaces on the server can communicate reliably with the corresponding iSCSI NICs or the same networks on the storage appliance.
Launch Server Manager in the server from the storage that you want to connect to.
We will now configure MPIO to enable support for iSCSI:
Launch iSCSI on the application server and select the iSCSI service to start automatically. Browse to the Discovery tab. Do the following for each iSCSI interface on the storage appliance:
Repeat the above for each IP address on the iSCSI storage appliance.
Browse to Targets. An entry will appear for each available volume/LUN that the server can see on the storage appliance.
For each volume, do the following:
The volume is now connected. However, we only have 1 session between the first NIC of the server and the first NIC of the storage appliance. We do not have a fault-tolerant connection enabled:
Repeat steps 1-14 for each volume that the server will connect to.
If you open Disk Management, your new volume(s) should appear. You can right-click a disk or volume that you connected, select properties, and browse to MPIO. From there, you should see the paths and the MPIO customizable policies that are being used by this disk.