White Paper- Windows Server High Availability with Microsoft MPIO

Figure 11. MPIO Properties GUI

The MPIO Properties page has 3 tabs and by default, the MPIO-ed Devices Tab is selected. The ―MPIO-ed Devices‖ tab shows the hardware ID’s of devices that will currently be managed by MPIO whenever they are present. The decision is based on their hardware id (ie. Vendor+Product string) matching one that is maintained by MPIO in its MPIOSupportedDeviceList (this is something that every DSM specifies in its INF at the time of installation). Figure 11 shows an example of a device is MPIO-ed.

The Add Button in Figure 11 allows for the administrator to specify another MPIO-ed device. Figure 12 shows the GUI generated when the Add tab in Figure 11 is clicked.

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Figure 12 Specifying MPIO-ed devices GUI

Note: The Vendor and Product ID’s needed in the “Add MPIO Support” dialog box shown above will be provided by the Storage provider, and are specific to each type of hardware.

Referring back to Figure 11, recall that there are 3 tabs in the GUI. The first tab ―MPIO-ed devices‖ Is explained in previous sections.

The ―Discover Multi-Paths‖ tab runs an algorithm for every device instance that is present on the system and determines if multiple instances actually represent the same LUN (through different paths). For such devices found, their hardware ids are presented for the Admin for MPIO’ing (they’ll get MSDSM support though).

Again, referring back to Figure 11, the ―DSM Install‖ tab can be used to install DSMs provided by the storage IHV.

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Figure 13 DSM Install Tab

Many storage arrays which are active/active and SPC-3 compliant will work using the Microsoft MPIO DSM. Some storage array partners also provide their own DSMs to use with the Microsoft MPIO architecture. These DSMs may be installed using the DSM Install tab in the MPIO properties Control Panel configuration utility:

IHV’s are expected to build their package using the MPIO Development Kit version 1.21 or higher from Microsoft. Many storage array partners provide their own installation package for their DSM. For Windows Server 2003, this installation package includes the MPIO core binaries signed by Microsoft. When such a package is run on Windows Server 2008, the operating system allows the vendor DSM to be installed, but prevents the MPIO binaries already present in Windows Server 2008 from being updated by the package. Thus the end result of running the vendor installation

rd

package is to preserve the core MPIO binaries already present in Windows Server 2008, but the 3 party provided DSM is added.

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How to configure the Load Balance policy for a LUN:

MPIO LUN load balancing is integrated with Disk Management. To configure MPIO LUN load balancing, start the Disk Management GUI

Figure 14 Disk Management

Figure 14 shows the Disk Management GUI. Right-Click the Desired disk (in this case C: ) to

change the policy for, and choose properties:

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