Enabling and Disabling Multipathing in the Windows Operating System

This section describes how to enable or disable multipathing for your J4500 array with the Windows operating system.

• About Multipathing

• How a Failover is Handled by Windows

• To Enable Multipathing in Windows Server 2008

• To Disable Multipathing in Windows Server 2008

About Multipathing

Multipathing of disks is handled through the Microsoft MPIO architecture in conjunction with a DSM (Device-Specific Module). For Windows Server 2008, use the built-in Microsoft generic DSM.

If you want to have multiple hosts accessing disks in the array, you must first set up zoning per host as described in Chapter 3, Adding and Zoning Array Storage Using CAM.

When you configure your J4500 array for a multipath support, Windows will initially see two copies of each disk from the OS since you are using two separate array connection paths (one to SAS A and one to SAS B). You will use MPIO to combine the two paths for each type of disk in the array so that the OS sees each multipathed disk as one disk.

After installing the built-in MPIO driver for Windows Server 2008, multipath disks will be combined into a single multipathed disk.

For example, Multipath Disks Seen in Windows Server 2008 Before and After MPIO shows how Windows Server 2008 Device Manager sees a server's four external multipath disks and two internal single path disks before [1] and after [2] MPIO.

Figure 4-7 Multipath Disks Seen in Windows Server 2008 Before and After MPIO

How a Failover is Handled by Windows

If you remove one path to a multipath disk, failover is handled automatically by MPIO. You continue to see the exact same list of disks in the Windows Device Manager and Windows Disk management views. However, you will see MPIO messages in the system event log indicating a failover has occurred.

To Enable Multipathing in Windows Server 2008

An MPIO utility is part of Windows Server 2008, but you must install it manually. For multipath support, you must have already done the following:

• Make sure that the J4500s that you want to setup for multipathing are properly connected to the host system and are up and running.

• You should have already downloaded and installed the Sun Storage J4500 array Windows Device Manager update driver package from the Sun software download site to ensure Windows will properly recognize the array.

• That any zoning of J4500 array storage using the Sun StorageTek Common Array Manager has been successfully completed (see Chapter 3, Adding and Zoning Array Storage Using CAM).

1. From the Windows Start menu, select Server Manager. See Start Menu with Server Manager Selected.
   

   Figure 4-8 Start Menu with Server Manager Selected

   
2. Select Features in the left-hand pane.

   The features summary page appears. See Server Manager Features Selected.

   
   

   Figure 4-9 Server Manager Features Selected

   
3. Click Add Features (right-side of page) to start the Add Features wizard.

   The Add Features wizard begins and presents the default Features selected and a list of optional features available for installation in your system. See Add Features Selection Page.

   
   

   Figure 4-10 Add Features Selection Page

   
4. Select the Multipath I/O option from the Message Queuing sublist, and then click Next.

   The Add Features wizard Confirm Installation Selections page appears. See Confirm Installation Selections Page.

   
   

   Figure 4-11 Confirm Installation Selections Page

   
5. Click Install.

   When the installation is finished, the Add Features wizard Installation Results page appears.

   
   

   Figure 4-12 Installation Results Page

   
6. Click Close.
7. Close the Server Manager main window.
8. Click Start and select Control Panel.
9. Double-click MPIO properties.

   After multipathing is installed, use MPIO properties to select the types of disks that will be multipathed.

   
   

   Figure 4-13 Example MPIO Properties

   
10. Select the Discover Multi-Paths tab.

    A list of all the disk drives by manufacturer ID and type are displayed. See Example MPIO Properties Discover Multi-Paths Tab.

    
    

    Figure 4-14 Example MPIO Properties Discover Multi-Paths Tab

    
11. Select the disk drives to multipath, and then click Add.
12. Click OK and reboot.

    At this point, MPIO is installed and configured for dual paths. The second path is hidden by Windows. By default, MPIO is configured for active passive path failover.

13. After the system reboots, configure MPIO properties for each disk, click Start, and the select Server Manager. See Start Menu with Server Manager Selected.
14. Select Device Manager from the Diagnostics sublist.

    An example view of disks is shown in Example of Dual-Path Disks as Seen in Device Manager.

    
    

    Figure 4-15 Example of Dual-Path Disks as Seen in Device Manager

    

    Next, you must make sure that the Load Balancing property for each disk is Failover Only.

15. Right-click a disk drive and select Properties.

    The device properties dialog box appears.

    
    

    Figure 4-16 Disk Device Properties Dialog Box with MPIO Tab Selected

    
16. Select the MPIO tab.
17. Choose Failover Only from the Load Balance Policy drop-down list. See Disk Device Properties Dialog Box with MPIO Tab Selected.

    The J4500 array only supports Failover.

18. Repeat steps 15 through 17 for each multi-path disk drive in the Device Manager window.

To Disable Multipathing in Windows Server 2008

Disabling multipathing to drives can be done at two levels:

• Remove drive types from MPIO control, but leave the MPIO feature enabled.

• Disable the MPIO feature.

The steps below describe both methods.

1. To remove drive types from MPIO control:
   1. From the Windows Start menu, select Administrative Tools, and then select MPIO.

      The MPIO Properties dialog box appears.

      
      

      Figure 4-17 MPIO Properties Dialog Box

      
   2. Highlight a device in the list, and then click Remove.
   3. Reboot the system as prompted.
   4. After the server has restarted, repeat Steps a through c for each additional device type to be removed.

      Once all multipath devices have been removed, you will next uninstall the multipath driver.

2. To disable the and MPIO feature:
   1. From the Windows Start menu, select Server Manager.
   2. Select Features from the left-hand pane.

      The features summary page appears.

      
      

      Figure 4-18 The Features Summary Page

      
   3. Select Remove Features (right-side of page) to start the Remove Features wizard.

      The Remove Features wizard begins.

   4. Select Multipath I/O from the Message Queuing sublist.
      

      Figure 4-19 Remove Features Wizard Page

      

      The Confirm Removal Selections page appears. See Confirm Removal Selections Page.

      
      

      Figure 4-20 Confirm Removal Selections Page

      
   5. Click Remove.

      The Removal Results page appears.

      
      

      Figure 4-21 Remove Results Page

      
   6. Click Close.

      You will be prompted to reboot the system.

   7. Click Yes to reboot.

      The server will shut down and restart.

   8. After the sever has restarted, the Removal Results page appears.
      

      Figure 4-22 Removal Results Page

      
   9. Click Close.

      Multipath has been disabled.