Task 13: Configure MPIO and Vendor MSDSM (Conditional)

DOCUMENT CATEGORY: Runbook SCOPE: MPIO and MSDSM configuration PURPOSE: Enable MPIO and configure vendor MSDSM so Windows correctly claims FC disks as multi-path volumes MASTER REFERENCE: Microsoft Learn — Enable External Storage

Status: Active

Skip this task if deploying Storage Spaces Direct (S2D)

This task applies only to disaggregated SAN deployments. If you are deploying with Storage Spaces Direct (hyperconverged), skip to Task 15: Complete Combined Script.

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Overview

Windows Multipath I/O (MPIO) aggregates multiple physical paths to a SAN LUN into a single logical disk, providing both redundancy and load distribution. MPIO must be installed as a Windows Feature, and the Microsoft Device Specific Module (MSDSM) must be configured with the hardware IDs for the specific SAN array in use. Without MSDSM, Windows presents each path as a separate disk rather than claiming them as a single multi-path volume.

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When to Run

Scenario	Run?
SAN disaggregated deployment	✅ Yes — all nodes
Storage Spaces Direct (S2D)	❌ Skip
MPIO already installed from previous deployment	✅ Yes — verify vendor hardware IDs still registered

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Prerequisites

Requirement	Details
Task 12 complete	FC HBA drivers installed
SAN array vendor	Vendor and model confirmed (hardware IDs needed)
FC fabric	Zoning configured (nodes can see SAN ports) — OR zoning will be completed post-Arc, before LUN access

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Variables from variables.yml

Path	Type	Description
cluster_nodes[].management_ip	string	PSRemoting target IP
storage.san_array_vendor	string	SAN array vendor name for documentation

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Step 1: Install MPIO Windows Feature

Direct (On Node)

Run on each node individually via console, KVM, or RDP.

Toolkit script: scripts/deploy/04-cluster-deployment/phase-03-os-configuration/task-13-configure-mpio-and-vendor-msdsm-conditional/powershell/Enable-MPIO-Direct.ps1

# Task 13 - Step 1: Install MPIO Feature (run on each node)
Add-WindowsFeature -Name Multipath-IO -IncludeManagementTools

Restart required

Restart each node after the feature installation completes before proceeding to Step 2.

Orchestrated Script

Run from the management server against all nodes.

Toolkit script: scripts/deploy/04-cluster-deployment/phase-03-os-configuration/task-13-configure-mpio-and-vendor-msdsm-conditional/powershell/Enable-MPIO-Orchestrated.ps1

# Task 13 - Step 1: Install MPIO Feature (orchestrated)
# variables.yml variables:
# cluster_nodes[].management_ip -> $ServerList

$ConfigPath = "$env:USERPROFILE\variables.yml"
$ServerList = (Get-Content $ConfigPath | Select-String 'management_ip:\s+"?([^"'' ]+)' |
    ForEach-Object { $_.Matches[0].Groups[1].Value.Trim() })

Invoke-Command -ComputerName $ServerList -ScriptBlock {
    Add-WindowsFeature -Name Multipath-IO -IncludeManagementTools
}

# Restart all nodes after feature installation
$ServerList | ForEach-Object { Restart-Computer -ComputerName $_ -Force }

Restart required

The script restarts all nodes immediately after feature installation. Wait for all nodes to return online before proceeding to Step 2.

Standalone Script

When to use: Use this option for a self-contained deployment without a shared configuration file.

Script: See azurelocal-toolkit → scripts/deploy/ for the standalone script for this task.

Content Pending

See toolkit repository for standalone implementation.

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Step 2: Configure Vendor MSDSM Hardware IDs

After all nodes have restarted, configure the Microsoft DSM with your SAN array's hardware IDs. Select the tab for your array vendor.

Pure Storage

# Task 13 - Step 2: Configure MSDSM for Pure Storage FlashArray
# Auto-claim FC disks via MPIO
Enable-MSDSMAutomaticClaim -BusType "FC"

# Register Pure Storage hardware IDs
New-MSDSMSupportedHW -VendorId "PURE" -ProductId "FlashArray"

# Set load balancing policy (Least Queue Depth recommended for All-Flash)
Set-MSDSMGlobalDefaultLoadBalancePolicy -Policy LQD

Dell PowerStore

# Task 13 - Step 2: Configure MSDSM for Dell PowerStore
Enable-MSDSMAutomaticClaim -BusType "FC"

# Register Dell PowerStore hardware IDs
New-MSDSMSupportedHW -VendorId "DELL" -ProductId "PowerStore"

# Set load balancing policy
Set-MSDSMGlobalDefaultLoadBalancePolicy -Policy LQD

HPE Alletra

# Task 13 - Step 2: Configure MSDSM for HPE Alletra
Enable-MSDSMAutomaticClaim -BusType "FC"

# Register HPE Alletra hardware IDs
New-MSDSMSupportedHW -VendorId "HP" -ProductId "OPEN-V"
New-MSDSMSupportedHW -VendorId "HP" -ProductId "Alletra"

# Set load balancing policy
Set-MSDSMGlobalDefaultLoadBalancePolicy -Policy LQD

Hitachi VSP

# Task 13 - Step 2: Configure MSDSM for Hitachi VSP
Enable-MSDSMAutomaticClaim -BusType "FC"

# Register Hitachi VSP hardware IDs
New-MSDSMSupportedHW -VendorId "HITACHI" -ProductId "OPEN-V"

# Set load balancing policy (Round Robin typical for VSP)
Set-MSDSMGlobalDefaultLoadBalancePolicy -Policy RR

NetApp ONTAP

# Task 13 - Step 2: Configure MSDSM for NetApp ONTAP
Enable-MSDSMAutomaticClaim -BusType "FC"

# Register NetApp ONTAP hardware IDs
New-MSDSMSupportedHW -VendorId "NETAPP" -ProductId "LUN"

# Set load balancing policy
Set-MSDSMGlobalDefaultLoadBalancePolicy -Policy LQD

Verify hardware IDs with your SAN vendor

The hardware IDs (VendorId / ProductId) shown above are commonly used values. Always verify the exact IDs for your specific array firmware version with your SAN vendor's Windows MPIO configuration guide.

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Verification

# Confirm MPIO is installed
(Get-WindowsFeature -Name Multipath-IO).InstallState

# Confirm supported hardware IDs are registered
Get-MSDSMSupportedHW | Format-Table VendorId, ProductId

# Confirm auto-claim is enabled for FC
mpclaim -s -d

Expected: InstallState = Installed; your vendor's IDs appear in the supported HW list; mpclaim shows disk paths (will show 0 paths until LUNs are presented and zoning is complete).

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Validation Checklist

• MPIO Windows feature installed on all nodes
• All nodes restarted after MPIO installation
• Vendor hardware IDs registered via New-MSDSMSupportedHW
• Enable-MSDSMAutomaticClaim -BusType "FC" confirmed on all nodes
• Load balance policy set

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Navigation

← Task 12: FC HBA Drivers · ↑ Phase 03 · Task 14: Verify LUN Presentation →

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Version Control

Version	Date	Author	Changes
1.0.0	2026-05-02	Azure Local Cloud	Initial release