Multipathing With Two Arrays and One Host

FIGURE 5-3 shows an example of cabling for multipath in a configuration with one host, with two HBAs on that host, and two arrays cabled together.

FIGURE 5-3 Cabling Example for Multipathing With Two Arrays and One Host

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Enabling and Disabling Multipathing in the Solaris Operating System

This sections describes how to enable and disable multipathing in the Solaris 10, update 6, operating system.

Use the stmsboot command to enable multipathing in the Solaris 10, update 6, operating system. stmsboot manages enumeration of multipath-capable devices with multipathing; it has these characteristics:

• Multipathing-enabled devices are enumerated under scsi_vhci(7D).
• Multipathing-disabled devices are enumerated under the physical controller.

This section describes the stmsboot(1M) administration program for multipathing.

Device Renaming

In the /dev and /devices trees, multipathing-enabled devices receive new names that indicate that they are under multipathing control.

• This means a device has a different name from its original name (after enabling) when it is under multipathing control.
• The stmsboot command automatically updates /etc/vfstab and dump configuration to reflect the device names changes when enabling or disabling Multipathing.
• One reboot is required for changes to take effect.

stmsboot Options

TABLE 5-3 describes the options supported by stmsboot(1M).

stmsboot Conditions

stmsboot enables and disables multipathing on the host, with these conditions:

• The utility automatically updates vfstab(4) and dumpadm(1M) configuration to reflect device-name changes.

• The -L and -l options display the mapping between multipathed and non- multipathed device names, only after changes to the multipathing configuration take effect; that is, following reboot after invoking stmsboot -e.
• ZFS datasets, including ZFS root datasets, are correctly handled by stmsboot.

  Type:

# stmsboot -e

# stmsboot -e
Warning: stmsboot operates on each supported multipath-capable controller detected in a host. In your system, these controllers are
	/devices/pci@780/pci@0/pci@8/SUNW,qlc@0/fp@0,0
	/devices/pci@780/pci@0/pci@8/SUNW,qlc@0,1/fp@0,0
	/devices/pci@7c0/pci@0/pci@1/pci@0,2/LSILogic,sas@1
	/devices/pci@7c0/pci@0/pci@1/pci@0,2/LSILogic,sas@1
	/devices/pci@7c0/pci@0/pci@1/pci@0,2/LSILogic,sas@2
	/devices/pci@7c0/pci@0/pci@9/LSILogic,sas@0
	/devices/pci@7c0/pci@0/pci@9/LSILogic,sas@0
 
If you do NOT wish to operate on these controllers, please quit stmsboot and re-invoke with -D { fp | mpt } to specify which controllers you wish to modify your multipathing configuration for.
 
Do you wish to continue? [y/n] (default: y) y
Checking mpxio status for driver fp
Checking mpxio status for driver mpt
WARNING: This operation will require a reboot.
Do you want to continue ? [y/n] (default: y) y
The changes will come into effect after rebooting the system.
Reboot the system now ? [y/n] (default: y) y
 

The following conditions apply to the stmsboot -e, -d, and -u options:

• Reboot immediately after running stmsboot.
• Ensure that eeprom(1m) boot device is set to boot from your current boot device; stmsboot reboots the machine to complete the operation.
• stmsboot saves a copy of your original /kernel/drv/mpt.conf and /etc/vfstab files before modifying them.

  Type:

# stmsboot -d

# stmsboot -d 
WARNING: stmsboot operates on each supported multipath-capable controller detected in a host. In your system, these controllers are
/devices/pci@780/pci@0/pci@8/SUNW,qlc@0/fp@0,0
/devices/pci@780/pci@0/pci@8/SUNW,qlc@0,1/fp@0,0
/devices/pci@7c0/pci@0/pci@1/pci@0,2/LSILogic,sas@1
/devices/pci@7c0/pci@0/pci@1/pci@0,2/LSILogic,sas@1
/devices/pci@7c0/pci@0/pci@1/pci@0,2/LSILogic,sas@2
/devices/pci@7c0/pci@0/pci@9/LSILogic,sas@0
/devices/pci@7c0/pci@0/pci@9/LSILogic,sas@0
 
If you do NOT wish to operate on these controllers, please quit stmsboot and re-invoke with -D { fp | mpt } to specify which controllers you wish to modify your multipathing configuration for.
 
Do you wish to continue? [y/n] (default: y) y
Checking mpxio status for driver fp
Checking mpxio status for driver mpt
WARNING: This operation will require a reboot.
Do you want to continue ? [y/n] (default: y) y
The changes will come into effect after rebooting the system.
Reboot the system now ? [y/n] (default: y) y
 

  Type:

# stmsboot -D mpt -e

  Type:

# stmsboot -D mpt -d

Configuring Multipathing on Selected Ports

To enable multipathing on specific ports and disable multipathing on others, edit the /kernel/drv/mpt.conf file. To update vfstab(4) and dumpadm(1M) configurations to reflect the changed device names, type:

# stmsboot -u

Dynamic Discovery of SAS Devices

SAS devices, added and removed dynamically with the mpt(7d) driver, enable your system to detect specific targets and LUNs attached, with these conditions:

• If you add or remove a device in your SAS domain, messages are written to the /var/adm/messages file indicating presence or removal.
• If a device has been added, it is visible to, and available by, the format(1m) command.

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Enabling and Disabling Multipathing in the Windows Operating System

This section describes how to enable and disable multipathing in the
Windows 2008 operating system.

1. From the Start menu, select Server Manager, as shown in FIGURE 5-4.

The Server Manager opens.

FIGURE 5-4 Start Menu With Server Manager Selection

2. Select Features from the list of folders on the left to open the Features panel, as shown in FIGURE 5-5.

FIGURE 5-5 Server Manager Feature Display

In the Features panel, you can click the Features Summary arrow to open or close the Features Summary and click the Features arrow to view the status of installed features.

3. Click Add Features to enable the Add Features Wizard.

The Add Features Wizard Select Features window opens with the default Features selected and a list of optional features available for installation in your system, as shown in FIGURE 5-6.

FIGURE 5-6 Add Features Wizard Select Features Window

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

5. Click Next.

The Add Features Wizard Confirm Installation Selections window opens, as shown in FIGURE 5-7.

FIGURE 5-7 Confirm Installation Selections Window

6. Click Install.

The Add Features Wizard Installation Results window opens as shown in FIGURE 5-8.

FIGURE 5-8 Add Features Wizard Installation Results Window

7. Click Close.

8. Close the Server Manager main window.

1. From the Windows Start menu (FIGURE 5-4), select Administrative Tools.

The MPIO Properties window, as shown in FIGURE 5-9..

FIGURE 5-9 MPIO Properties Window

2. Select the Discover Multi-Paths tab, as shown in FIGURE 5-10.

FIGURE 5-10 MPIO Properties Window Device Multi-Paths Tab

3. Highlight the Device Hardware for which you want to discover multipaths, as shown in FIGURE 5-11.

FIGURE 5-11 Highlighted Device Hardware for Discovering Multipaths

4. Click OK.

The Reboot Required window opens, as shown in FIGURE 5-12.

FIGURE 5-12 Reboot Required Window

5. Click Yes.

1. From the Windows Start menu, select Server Manager, as shown in FIGURE 5-4.

2. Select Diagnostics > Device Manager from the list of folders on the left to open the Device Manager window, as shown in FIGURE 5-13.

FIGURE 5-13 Device Manager Window

3. Click the Device name.

4. Click Disk drives.

The list of disk drives opens, as shown in FIGURE 5-13.

5. Move your cursor over the device drive name for which you want information.

6. Right-click to open a menu and select Properties, as shown in FIGURE 5-14.

FIGURE 5-14 Menu to Modify Device Configuration

The Disk Drive Properties window opens, as shown in FIGURE 5-15.

FIGURE 5-15 Disk Drive Properties Window

7. Use the drop-down menu to select a load-balancing policy, as shown in FIGURE 5-16.

The choices for load-balancing policies are listed in TABLE 5-4. By default, the Fail Over Policy is configured. For best results with the J4200/J4400 array, use the Round Robin policy.

FIGURE 5-16 Round Robin Load Balance Policy Selected

8. Click OK.

1. From the Windows Start menu, select Administrative Tools > MPIO, as shown in FIGURE 5-17.

The MPIO Properties window opens, as shown in FIGURE 5-18.

FIGURE 5-17 Selecting Administrative Tools > MPIO From the Start Menu

FIGURE 5-18 MPIO Properties Window

2. Highlight a device in the list, as shown in FIGURE 5-19.

FIGURE 5-19 Highlighting Device For Which to Disable Multipathing

3. Click Remove.

The Reboot Required window opens, as shown in FIGURE 5-20.

FIGURE 5-20 Reboot Required Window

4. Click Yes.

The system reboots.

5. After reboot, select Administrative Tools > MPIO from the Windows Start menu.

The MPIO Properties window opens, showing the device removed from the list, as shown in FIGURE 5-21.

FIGURE 5-21 MPIO Properties Window With Device Removed From List

6. Repeat Step 2 through Step 5 until all devices are removed from the Device Hardware Id list.

7. From the Windows Start menu, select Server Manager to open the Server Manager window.

8. Select Features from the list of folders on the left to open the Features panel, as shown in FIGURE 5-22.

FIGURE 5-22 Server Manager Window With Features Panel Open

9. Select Remove Features.

The Remove Features Wizard window opens, as shown in FIGURE 5-23.

FIGURE 5-23 Remove Features Wizard Window

10. Highlight Multipath I/O from the Message Queuing sublist.

The Confirm Removal Selections window opens, as shown in FIGURE 5-24.

FIGURE 5-24 Confirm Removal Selections Window

11. Click Remove.

The Removal Results window opens, as shown in FIGURE 5-25.

FIGURE 5-25 Removal Results Window

12. Click Close.

The system asks if you want to restart the server now, as shown in FIGURE 5-26.

FIGURE 5-26 Restart Now Window

13. Click Yes.

When the sever has restarted, the Removal Results window opens, as shown in FIGURE 5-27.

FIGURE 5-27 Removal Results Window

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Enabling and Disabling Multipathing in the Linux Operating System

This section describes how to enable and disable multipathing in supported versions of the Linux operating system.

1. Attach a J4200 or a J4400 to a server with a supported version of Linux installed.

2. On the server, edit or create the /etc/multipath.conf file.

3. Reboot the server.

4. After the reboot, make sure that the OS discovers all the disks in the J4200/J4400 arrays either by using the Linux commands, fdisk or lsscsi.

5. Partition any disks you want to the desired sizes.

6. Use the Linux command modprobe to add the loadable kernel modules dm-multipath and dm-round-robin.

# modprobe dm-multipath

# modprobe dm-round-robin

7. Start the multipathd daemon.

For Linux SUSE 9, use the following command:

# multipathd -v0

For other supported Linux versions, use the following command:

# service multipathd start

8. Start the multipathing device mapper target autoconfig.

# multipath -v2

9. List the multipath devices that have been created.

# multipath -ll

The output should list the same number of devices as there are disks in the J4200/J4400 arrays; it will look similar to the following:

1. If a RAID volume, LVM volume, or volume mount have been placed over the device node of the multipathed disk, quiesce the volume.

2. Use the multipath -f command to disable multipathing to a specific device.

multipath -f mpath1

3. Use the multipath -F command to disable multipathing on all multipathed devices.

multipath -F