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

Managing Secure Path
84 Secure Path v3.0C for Linux and Linux Workgroup Edition Installation and Reference Guide
# spmgr select -p path_instance
This command selects the indicated path and makes that path Active. This
parameter, path_instance, satisfies the path equation because it contains the
necessary components of HBA, controller port, and device. Therefore, no other
switches or parameters are required to identify the path.
Example:
# spmgr select –p hsx-mod-1-0-0-2
Result: The Secure Path driver selects path hsx-mod-1-0-0-2 for I/O.
The prefer and unprefer commands
On an array, each LUN may be assigned to a particular controller and be available
for selection at startup.
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, the preferred path attribute on Secure Path
must be set. For the HSG80, HSV110 and HSV100, the preferred controller can
be set. For the MSA1000, the preferred controller is set up by default.
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 driver.
Therefore, the path may be maintained permanently until removed or another
preferred path is selected.
To support adding and removing preferred paths, spmgr provides two
commands, spmgr prefer and spmgr unprefer.These two commands
each require a single parameter: the path_instance.