Installation and Reference Guide HP StorageWorks Secure Path 3.0F Service Pack 4 for HP-UX 11i v1.0 and 11i v2.0 (5697-8001, March 2009)

Because Secure Path can have more than one path to each controller, you can further specify a
preferred path. To differentiate between the controller unit attribute of preferred_path and the
Secure Path preferred path, this document refers to the controller-based preferred-path attribute as the
preferred controller.
The preferred path assignment lets you control setting static load balancing because the path chosen
determines which adapter and controller port are designated as the default path at system startup.
One preferred path can be assigned to each controller for each LUN.
For the preferred path feature to work, you must set either the preferred controller LUN attribute on
the array or the preferred path attribute on Secure Path, or both the preferred controller and preferred
path attributes.
Following are the examples of preferred path priority:
• Controller attribute priority
The preferred controller attribute has priority over the preferred path attribute. For example, if you
have preferred controller A to a LUN and have also set the preferred path to that LUN as a path
to controller B, a restore or reboot results in a path on controller A being selected as active.
• Controller attribute and path priority
If you have preferred controller A to a LUN and have also set the preferred path to that LUN as
a path to controller A, a restore or reboot results in the preferred path on controller A being selected
as active.
• Path priority
If you have no controller preferred to a LUN and have a preferred path set for that LUN, then a
restore or reboot results in the preferred path being selected as active.
To set the preferred controller LUN attribute for the HSG80, use the HSG80 ADD or SET commands
and the preferred-path attribute for preferring a unit to this or other controller. For example, you can
assign a unit as preferred to this controller by entering the following command:
HSG80> SET D6 PREFERRED_PATH = THIS_CONTROLLER
To set the preferred controller LUN attribute for the HSV110, log on to the Command View EVA and
complete the following steps for preferring a virtual disk to controller A or controller B:
1. Select the virtual disk you want to modify in the navigation pane.
2. Set the Preferred Path/Mode to Path A-Failover Only or Path B-Failover Only on the Virtual Disk
Active Properties page.
3. Click Save Changes at the top of the Content pane to direct the system to process the change.
A status page is displayed indicating the status of the modification completed successfully.
4. Click OK.
An updated properties page is displayed.
NOTE:
Path A - Failover/failback and Path B - Failover/failback are not supported on Secure Path for
HP-UX. This feature is designed for operating systems that cannot run Secure Path.
At any time you can select a different path to be used for I/O. The selected path is not preserved for
a server power cycle or operating system restart. To preserve an active path through power cycles
and restarts, identify it as a preferred path. Preferred path identifications are marked by the Secure
Path driver in the running system and the identifications are stored in the configuration files for that
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