HP StorageWorks Secure Path V3.0C for Linux and Linux Workgroup Edition Installation and Reference Guide (AA-RU7VD-TE, February 2004)

Managing Secure Path
85Secure Path v3.0C for Linux and Linux Workgroup Edition Installation and Reference Guide
# spmgr prefer path_instance
This command instructs the Secure Path driver to mark a designated path as
Preferred. If load balance is disabled, this path becomes the active I/O path.
Additionally, spmgr adds this path_instance to the Secure Path driver's
configuration file and upon reboot of the server, the preferred paths will be
restored.
Syntax:
# spmgr prefer path_instance
Example:
# spmgr prefer hsx_mod-1-0-0-2
This command requires that the path_instance be supplied on the command
line. The
path_instance is provided in the spmgr display listings.
# 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:
# spmgr unprefer hsx_mod-1-0-0-2
Impact of Load Balancing and active Paths
For storage systems, preferred path and selected path are meaningless
designations when you have enabled Load Balancing. Load Balancing 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, the Secure Path driver attempts to use all the
available paths to a LUN in a round-robin fashion.
If Load Balancing is enabled and you set the path as Preferred, the system
performs the following actions:
■ The driver marks the path as Preferred, but the path will not be used as
Preferred until the Load Balancing is turned off.