Read this guide to learn how to install and configure Multipath Input/Out (MPIO) to claim Fiber Channel (FC) LUMs on a Windows Server 2022.
Overview
To provide redundancy, LUMs are usually assigned to the Primary and Secondary WWPN of an FC HBA adapter port. Essentially, the FC LUM is assigned to two “paths.”
The benefit of multipath LUM assignment is that if one of the FC HBA ports breaks, the host server can still access the disk – leading to high availability.
However, with this multipath configuration, the assigned LUM appears as multiple disks in Windows Disk Management. In the screenshot below, the 1024 GB (1 TB) disk is a single Fiber Channel LUM.
However, the disk appears to Windows as two disks. The way to make this a single disk is to install and configure MPIO on the Windows Server.
The steps below outline the details.
Step 1: Install the MPIO Windows Server Feature
To install MPIO using Server Manager, follow these steps.
You can also complete this task with PowerShell (run PowerShell as administrator) by running the command below:
Install-WindowsFeature -Name multipath-io
Installing with PowerShell is faster. However, if you prefer GUI, here are the steps:
- From Server Manager, click Manage > Add Roles and Features.
- Continue clicking Next until you get to the “Select features” node. Check the “Multipath I/O” checkbox and click next.
- Finally, continue clicking Next, then, on the final page, click Install.
Wait for the installation to complete, then, proceed to Step 2 below.
Step 2: Configure MPIO to Claim the FC Disks
You can configure using the MPIO GUI tool or with PowerShell. I have explained how to do both in the following subsections
Option 1: Claim the FC Disks with the MPIO Tool
Use this option if you’re claiming FC disks in a Windows Server with Desktop Experience (GUI). If you’re configuring MPIO in a Windows Server Core, use option 2.
1. From Server Manager, click Tools and select MPIO.
- Then, click the “Discover Multi-Paths” tab, select the Device Id under SPC-3 complaint, and click Add. Wait until the “MPIO operation completed successfully” message and restart the server.
Option 2: Claim the FC Disks with the MPIO PowerShell Commands
If you’re configuring MPIO to claim FC disks in a Windows Server Core installation, this is your only option as Server Core does not have GUI.
Before configuring MPIO, run Get-Disk to list all available disks. The Fiber Channel LUMs will be displayed as multiple disks.
To help you understand the benefit of MPIO, the server from the screenshot below has been assigned 1x 2GB LUM and 3x 2TB LUMS. However, in my screenshot, there are 16 disks. This means that each LUM appears 3 times.
I have highlighted the 2 GB LUMs in my screenshots.
To combine the disks into 1 LUM, run this command on each host:
- Confirm that the device is not in the MPIO list by running this command.
Get-MSDSMSupportedHw
- To see available MPIO devices, run this command
Get-MPIOAvailableHW
The first command shows the pseudo-Micorosft MPIO device. Meanwhile, the second command shows the MPIO device that I can add.
- To add this device to the list and claim the FC LUMs (combine them into single disks in Disk Management), run this command:
New-MSDSMSupportedHW -ProductID "VendorX" -VendorID "ProductY"
- After adding the device, re-running the Get-MSDSMSupportedHw lists the newly added MPIO device.
- Finally, run the Update-MPIOClaimedHW command and press enter when it prompts that a restart may be required. If a restart is not required, the command will return false.
Now, re-run Get-Disk and see the magic – all the disks have been combined into 1 LUM! My server now has 1x 2GB and 3x 2TB disks.
Step 3: Configure the Claimed Disk in Disk Management
When the server restarts, open Disk Management (right-click Start Menu > Computer Management > Disk Management).
Disk Management shows the FC LUM as a single disk.
Bring the disk online, Initialize it, and create a volume as normal,
Finally, create a volume (or multiple volumes as you wish) and format the disk.
Conclusion
If you use Fiber Channel HBA, LUMs may appear as multiple disks in Disk Management. Before you can use the disk, you must first use MPIO to “claim” the disks so they appear as a single disk.
This is achieved by installing the Windows Server Multipath I/O feature and configuring MPIO. After that, you can use the disk however you wish.
I hope that this simple guide has saved your day. If I saved you tons of time, I’d like to hear about it. Let me know by responding to the “What this page helpful” below.
