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)

driver. Therefore, the path may be maintained permanently until removed or another preferred path
is selected.
prefer and unprefer commands
To support adding and removing preferred paths, spmgr provides two commands, spmgr prefer
and spmgr unprefer. These two commands each require the path instance parameter.
NOTE:
The results of these commands are stored in configuration files, and the files persist across reboots.
Because these commands make dynamic changes to the driver in kernel space, spmgr update must
be executed for the new configuration to persist across reboots.
This section describes the following:
• # spmgr prefer path_instance
• # spmgr unprefer path_instance
# spmgr prefer path_instance
This command instructs the Secure Path driver to mark a selected path as preferred. If load balance
is disabled, this path becomes the active I/O path. Additionally, spmgr adds the specified
path_instance to the Secure Path driver's configuration file and upon reboot of the server, the preferred
paths get restored.
Syntax:
# spmgr prefer path_instance
For this command to execute properly, you need to supply the path_instance on the command line.
The path_instance is provided in the spmgr display listings.
Example:
# spmgr prefer c21t0d5
# spmgr unprefer path_instance
This command instructs the Secure Path driver to unmark the path as a preferred path. Additionally,
the configuration file for the Secure Path driver is modified by removing the preferred path markings.
Syntax:
# spmgr unprefer path_instance
Example: path verification
# spmgr unprefer c21t0d5
Impact of load balancing and active paths
Preferred path and selected path are meaningless designations when you enable load balancing.
Load balancing treats all paths equally and directs I/O to all available paths. In other words, load
balancing is a higher priority than preferred or selected paths.
When load balancing is enabled, as a default, the Secure Path for Active-Passive device attempts to
use all the available paths to a LUN in a round-robin fashion.
Secure Path for Active-Passive disk arrays58