Installing and Configuring MPIO

This section explains how to install and configure Microsoft Multipath I/O (MPIO) on Windows Server 2008 R2.

Install MPIO on Windows Server 2008 R2

MPIO is an optional feature in Windows Server 2008 R2, and is not installed by default. To install MPIO on your server running Windows Server 2008 R2, perform the following steps.

To add MPIO on a server running Windows Server 2008 R2

1. Open Server Manager. To open Server Manager, click Start, point to Administrative Tools, and then click Server Manager.
   
2. In the Server Manager tree, click Features.
   
3. In the Features area, click Add Features.
   
4. In the Add Features Wizard, on the Select Features page, select the Multipath I/O check box, and then click Next.
   
5. On the Confirm Installation Selections page, click Install.
   
6. When the installation has completed, on the Installation Results page, click Close. When prompted to restart the computer, click Yes.
   
7. After restarting the computer, the computer finalizes the MPIO installation.
   
8. Click Close.
   

MPIO configuration and DSM installation

When MPIO is installed, the Microsoft device-specific module (DSM) is also installed, as well as an MPIO control panel. The control panel can be used to do the following:

• Configure MPIO functionality
  
• Install additional storage DSMs
  
• Create MPIO configuration reports
  

Open the MPIO control panel

Open the MPIO control panel either by using the Windows Server 2008 R2 Control Panel or by using Administrative Tools.

To open the MPIO control panel by using the Windows Server 2008 R2 Control Panel

1. On the Windows Server 2008 R2 desktop, click Start, click Control Panel, and then in the Views list, click Large Icons.
   
2. Click MPIO.
   
3. On the User Account Control page, click Continue.
   

To open the MPIO control panel by using Administrative Tools

1. On the Windows Server 2008 R2 desktop, click Start, point to Administrative Tools, and then click MPIO.
   
2. On the User Account Control page, click Continue.
   

The MPIO control panel opens to the Properties dialog box.

Note
To access the MPIO control panel on Server Core installations, open a command prompt and type MPIOCPL.EXE.

MPIO Properties dialog box

The MPIO Properties dialog box has four tabs:

• MPIO Devices   By default, this tab is selected. This tab displays the hardware IDs of the devices that are managed by MPIO whenever they are present. It is based on a hardware ID (for example, a vendor plus product string) that matches an ID that is maintained by MPIO in the MPIOSupportedDeviceList, which every DSM specifies in its Information File (INF) at the time of installation.
  
  To specify another MPIO device, on the MPIO Devices tab, click Add.
  
  

  Note

  In the Add MPIO Support dialog box, the vendor ID (VID) and product ID (PID) that are needed are provided by the storage provider, and are specific to each type of hardware. You can list the VID and PID for storage that are already connected to the server by using the mpclaim tool at the command prompt. The hardware ID is an 8-character VID plus a 16-character PID. This combination is sometimes referred to as a VID/PID. For more information about the mpclaim tool, see Referencing MPCLAIM Examples.

• Discover Multi-Paths   Use this tab to run an algorithm for every device instance that is present on the system and determine if multiple instances actually represent the same Logical Unit Number (LUN) through different paths. For such devices found, their hardware IDs are presented to the administrator for use with MPIO (which includes Microsoft DSM support). You can also use this tab to add Device IDs for Fibre Channel devices that use the Microsoft DSM.
  
  

  Note
  Devices that are connected by using Microsoft Internet SCSI (iSCSI) are not displayed on the Discover Multi-Paths tab.

• DSM Install   This tab can be used for installing DSMs that are provided by the storage independent hardware vendor (IHV).
  
  Many storage arrays that are SPC-3 compliant will work by using the MPIO Microsoft DSM. Some storage array partners also provide their own DSMs to use with the MPIO architecture.
  
  

  Note
  We recommend using vendor installation software to install the vendor’s DSM. If the vendor does not have a DSM setup tool, you can alternatively install the vendor’s DSM by using the DSM Install tab on the MPIO control panel.

• Configuration Snapshot   This tab allows you to save the current Microsoft Multipath I/O (MPIO) configuration to a text file that you can review for troubleshooting or comparison purposes at a later time.
  
  The report includes information on the device-specific module (DSM) that is being used, the number of paths, and the path state.
  
  You can also save this configuration at a command prompt by using the mpclaim command. For information about how to use mpclaim, in an elevated command prompt, type run mpcliam /?. For more information, see Referencing MPCLAIM Examples.
  

Claim iSCSI-attached devices for use with MPIO

Note
This process causes the Microsoft DSM to claim all iSCSI-attached devices regardless of their vendor ID and product ID settings. For information about how to control this behavior on an individual VID/PID basis, see Referencing MPCLAIM Examples.

To claim an iSCSI-attached device for use with MPIO

1. Open the MPIO control panel, and then click the Discover Multi-Paths tab.
   
2. Select the Add support for iSCSI devices check box, and then click Add. When prompted to restart the computer, click Yes.
   
3. When the computer restarts, the MPIO Devices tab lists the additional hardware ID “MSFT2005iSCSIBusType_0x9.” When this hardware ID is listed, all iSCSI bus attached devices will be claimed by the Microsoft DSM.
   

Configure the load-balancing policy setting for a Logical Unit Number (LUN)

MPIO LUN load balancing is integrated with Disk Management. To configure MPIO LUN load balancing, open the Disk Management graphical user interface.

Note
Before you can configure the load-balancing policy setting by using Disk Management, the device must first be claimed by MPIO. If you need to preselect a policy setting for disks that are not yet present, see Referencing MPCLAIM Examples.

To configure the load-balancing policy setting for a LUN

1. Open Disk Management. To open Disk Management, on the Windows desktop, click Start; in the Start Search field, type diskmgmt.msc; and then, in the Programs list, click diskmgmt.
   
2. Right-click the disk for which you want to change the policy setting, and then click Properties.
   
3. On the MPIO tab, in the Select the MPIO policy list, click the load-balancing policy setting that you want.
   
4. If desired, click Details to view additional information about the currently configured DSM.
   

   Note
   When using a DSM other than a Microsoft DSM, the DSM vendor may use a separate interface to manage these policies.

   
   

   Note
   For information about DSM timer counters, see Configuring MPIO Timers.

   
   

Configure the MPIO Failback policy setting

If you use the Failover Only load-balancing policy setting, MPIO failback allows the configuration of a preferred I/O path to the storage, and allows automatic failback to be the preferred path if desired.
Consider the following scenario:

• The computer that is running Windows Server 2008 R2 is configured by using MPIO and has two connections to storage, Path A and Path B.
  
• Path A is configured as the active/optimized path, and is set as the preferred path.
  
• Path B is configured as a standby path.
  

If Path A fails, Path B is used. If Path A recovers thereafter, Path A becomes the active path again, and Path B is set to standby again.

To configure the preferred path setting

1. Open Disk Management. To open Disk Management, on the Windows desktop, click Start; in the Start Search field, type diskmgmt.msc; and then, in the Programs list, click diskmgmt.
   
2. Right-click the disk for which you want to change the policy setting, and then click Properties.
   
3. On the MPIO tab, double-click the path that you want to designate as a preferred path.
   

   Note
   The setting only works with the Failover Only MPIO policy setting.

   
   
4. Select the Preferred check box, and then click OK.
   

Install MPIO on Server Core installations of Windows Server 2008 R2

Because the Server Core installation of Windows Server 2008 R2 does not include the Server Manager interface, you must install MPIO by using a command prompt. Until you enable MPIO by using the DISM tool, you cannot use the mpclaim command.
Open a command prompt to run the following commands. After typing a command, press ENTER.

 

Task	Command
Determine which features are currently installed	Dism /online /get-features
Enable MPIO	Dism /online /enable-feature:MultipathIo Important When using DISM to enable or disable features, the feature name is case-sensitive.
Disable MPIO	Dism /online /disable-feature:MultipathIo
Manage the MPIO configuration after MPIO is enabled	mpclaim
Access the MPIO control panel (new in Windows Server 2008 R2)	MPIOCPL.exe

To enable Windows PowerShell™ on a Server Core installation, you must enable the following features by using these commands at an administrator command prompt:
dism /online /enable-feature:NetFx2-ServerCore
dism /online /enable-feature:NetFx2-W0W64_
dism /online /enable-feature:MicrosoftWindowsPowerShell_
dism /online /enable-feature:MicrosoftWindowsPowerShell-W0W64