Troubleshooting MPIO: Why Disk Management Lacks the Option in Windows Server 2019

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This document addresses a specific change implemented in Windows Server 2019 concerning the management of Multipath I/O (MPIO). Specifically, it highlights the absence of the MPIO configuration option within the Disk Management interface, a feature that was readily available in previous iterations of Windows Server. This alteration can present a challenge for system administrators accustomed to utilizing the graphical user interface (GUI) for managing MPIO settings. This article aims to clarify this modification and provide a practical workaround using PowerShell for configuring MPIO in Windows Server 2019.

Symptom: Missing MPIO Option in Disk Management¶

Upon installing the Multipath I/O feature on a server operating Windows Server 2019 build 17763, administrators may encounter an unexpected change in the Disk Management console. In prior versions of Windows Server, navigating to Disk Management and then accessing the Microsoft Storage Space Device Properties would reveal an option to configure MPIO settings. This familiar pathway for managing MPIO configurations is conspicuously absent in Windows Server 2019.

This absence means that the traditional GUI-based method for enabling and configuring MPIO policies, load balancing algorithms, and other related settings is no longer available through the Disk Management tool in this specific version of Windows Server. Users expecting to find the MPIO option in its usual location will find that it is no longer present, potentially leading to confusion and requiring them to adopt alternative methods for managing MPIO. This change primarily impacts administrators who rely on the Disk Management GUI for storage configuration tasks and may not be immediately aware of the shift to PowerShell-based management.

Workaround: Utilizing PowerShell for MPIO Configuration¶

To effectively manage MPIO in Windows Server 2019, the recommended and primary workaround is to leverage the power of PowerShell cmdlets. PowerShell provides a robust command-line interface and scripting language that offers granular control over various aspects of the Windows operating system, including storage management and MPIO configuration. While the GUI option is no longer available in Disk Management, PowerShell provides a more than capable alternative, offering even greater flexibility and automation capabilities.

Here are the steps and examples of PowerShell cmdlets to configure MPIO:

Retrieving the Current MPIO Policy¶

To begin, it’s often helpful to determine the currently active MPIO policy. This allows you to understand the existing configuration before making any modifications. The Get-MSDSMGlobalDefaultLoadBalancePolicy cmdlet serves this purpose.

Get-MSDSMGlobalDefaultLoadBalancePolicy

Executing this command in PowerShell will output the currently configured global default load balance policy for MPIO on the server. Understanding the current policy is crucial before deciding on any changes to ensure that modifications align with the desired storage performance and redundancy requirements.

Setting the MPIO Policy¶

To modify or set a new MPIO policy, the Set-MSDSMGlobalDefaultLoadBalancePolicy cmdlet is employed. This cmdlet allows you to define the load balancing algorithm that MPIO will utilize when managing multiple paths to storage devices. Various policies are available, each with its own characteristics and suitability for different storage environments.

For instance, to configure the MPIO policy to Round Robin, which distributes I/O requests evenly across all available paths, you would use the following command:

Set-MSDSMGlobalDefaultLoadBalancePolicy -Policy RR

In this command, -Policy RR specifies the Round Robin policy. Other available policies include:

• FOO (Fail Over Only): Actively uses a single path and only switches to another path if the active path fails. This is primarily for active-passive storage configurations.
• RRWS (Round Robin with Subset): Similar to Round Robin but uses a subset of paths initially and only utilizes other paths if the primary paths become saturated.
• LEASTBLOCKS: Routes I/O to the path with the fewest outstanding blocks. This policy attempts to balance load based on queue depth.
• DYNAMICROUNDROBIN: Dynamically adjusts path usage based on real-time performance metrics.

The choice of policy depends on the specific storage infrastructure, performance requirements, and desired level of redundancy. Consult storage vendor documentation and best practices to determine the most appropriate policy for your environment.

Verifying MPIO Configuration¶

After setting the MPIO policy or making other configurations, it is essential to verify that the changes have been applied correctly. You can re-run the Get-MSDSMGlobalDefaultLoadBalancePolicy cmdlet to confirm the currently active policy. Additionally, the Get-MPIOPath cmdlet can be used to retrieve detailed information about the paths managed by MPIO, including their status and load balancing policy in use.

Get-MPIOPath

This command provides a comprehensive view of the MPIO configuration, allowing administrators to ensure that the desired settings are in place and that paths are operating as expected. Regular verification is a good practice to maintain storage performance and resilience.

Additional MPIO PowerShell Cmdlets¶

PowerShell offers a suite of cmdlets for comprehensive MPIO management. Some other useful cmdlets include:

• Enable-MSDSMAutomaticClaim: Enables automatic claiming of storage devices by the Microsoft DSM (Device Specific Module) for MPIO.
• Disable-MSDSMAutomaticClaim: Disables automatic claiming, useful for managing specific devices manually.
• Add-MSDSMSupportedHW: Adds hardware IDs to the list of devices supported by the Microsoft DSM, allowing MPIO to manage these devices.
• Remove-MSDSMSupportedHW: Removes hardware IDs from the supported list.
• Get-MSDSMSupportedHW: Retrieves the list of hardware IDs supported by the Microsoft DSM.

These cmdlets, combined with the policy setting cmdlets, provide a complete toolkit for managing MPIO in Windows Server 2019 and later versions. Mastering these PowerShell commands empowers administrators to effectively configure and maintain MPIO for optimal storage performance and high availability.

Why PowerShell and Not GUI?¶

The decision to remove the MPIO option from the Disk Management GUI in Windows Server 2019 likely stems from a broader trend towards command-line and automation-driven server management. PowerShell offers several advantages over GUI-based tools in enterprise environments:

• Automation: PowerShell scripts can automate complex MPIO configurations and management tasks, reducing manual effort and potential errors. Scripts can be easily scheduled and reused across multiple servers.
• Scalability: Managing MPIO across a large number of servers is far more efficient with PowerShell. Scripts can be executed remotely on multiple systems simultaneously, a task that would be cumbersome and time-consuming using a GUI.
• Consistency: PowerShell scripts ensure consistent configurations across servers, reducing configuration drift and simplifying troubleshooting.
• Advanced Configuration: PowerShell provides access to more advanced MPIO settings and customization options that may not be exposed in a simplified GUI.
• Scripting and Integration: PowerShell seamlessly integrates with other management tools and scripting languages, enabling end-to-end automation of infrastructure tasks.

While the initial shift from a GUI to PowerShell might require a learning curve for administrators accustomed to graphical tools, the long-term benefits in terms of efficiency, scalability, and automation capabilities are significant, especially in modern, large-scale data centers and cloud environments. Microsoft is increasingly focusing on PowerShell as the primary management interface for Windows Server, reflecting the industry’s move towards infrastructure as code and automated management practices.

Conclusion¶

The absence of the MPIO option in Disk Management within Windows Server 2019 is a deliberate change that necessitates the use of PowerShell for MPIO configuration. While this might represent a shift in workflow for some administrators, PowerShell provides a powerful and versatile alternative for managing MPIO. By utilizing cmdlets such as Get-MSDSMGlobalDefaultLoadBalancePolicy and Set-MSDSMGlobalDefaultLoadBalancePolicy, administrators can effectively configure and manage MPIO policies, ensuring optimal storage performance and resilience. Embracing PowerShell for MPIO management aligns with modern server administration practices focused on automation, scalability, and consistent configuration management.

We encourage you to explore the full range of MPIO PowerShell cmdlets and integrate them into your server management workflows. This approach not only addresses the change in Windows Server 2019 but also enhances your overall efficiency and control over your storage infrastructure.

Do you have any experiences with managing MPIO in Windows Server 2019 using PowerShell? Share your tips, questions, or challenges in the comments below!