How to Setup MPIO to Claim FC LUMs in Windows Server 2022

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:

1. From Server Manager, click Manage > Add Roles and Features.

2. Continue clicking Next until you get to the “Select features” node. Check the “Multipath I/O” checkbox and click next.

3. 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

1. From Server Manager, click Tools and select MPIO.

2. 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. 

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.

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