HP StorageWorks SAN Virtualization Services Platform Administrator Guide (5697-0934, May 2011)

HP-UX 11iv3
Use native multipathing.
Linux multipathing
Support for multipathing with Linux depends on the version of Linux you have installed:
• For RHEL v4 and RHEL v5 update 2, you must use the QLogic failover driver.
• For RHEL v5 update 5 and above you must use the inbox driver with Device Mapper Multipath
support.
Please visit http://spock.corp.hp.com for the latest information regarding your operating system.
Installing the QLogic failover driver
1. Go to http://h18006.www1.hp.com/products/sanworks/softwaredrivers/multipathoptions/
linux.html.
2. Select the QLogic driver.
3. Select the RedHat or SUSE Linux operating system.
4. Click Download for that product. Optionally, you can select the correct product description
to verify you made the correct selection, and download from that page.
5. After downloading the driver to the server, run the install with the -f qualifier. This installs
the driver with failover capabilities.
6. Once the install is complete, configure the driver parameters to work with the EVA array, and
then create a new initrd to reflect the parameter changes. This can be accomplished by running
the set_parm utility (/opt/hp/src/hp_qla2x00src/set_parm). Choose option 1, and
then select Yes when asked to create a new initrd.
After installing the multipath drivers, it is a good idea to verify the paths between the server and
the DPM. Enter the following command:
[prompt]# hp_rescan –a
In response, you should see a path through both ports to every attached device.
If you encounter an issue with the Linux device paths changing between server power cycles
because the persistent binding is not configured correctly, use the following procedure:
1. Install the failover QLogic multipath driver.
2. Before mapping any LUNs to the host, open the SANsurfer GUI and choose the first port.
3. Select the persistent binding tab and select the check box under "Bind All" and choose a
target ID for each of the targets mapped and select Save.
4. Perform a similar binding on the other HBA port.
5. Map the LUNs from the VSM to this host and scan for the virtual disks at the host using the
hp_rescan -a utility.
6. Refresh the SANsurfer GUI and change the target ID of one target (for example, change it to
3). Observe that the rest of the targets are grayed out.
7. Create a new initrd image using mkinitrd <initrd image path> <kernel_version>.
8. Edit the file /boot/grub/menu.lst to boot with the new initrd image and reboot. During
the reboot, observe that the new target ID is used for all the LUNs. This can be verified when
we display all the LUNs using lssd. On subsequent reboots the device IDs should not change.
Using the native Device Mapper Multipath
For instructions on using the native Linux Device Mapper Multipath, please see the related reference
guide available from the SPOCK web page at http://www.hp.com/storage/spock. To access the
guide, select Solution:Linux in the left hand column under Application Notes.
26 Adding devices to the domain