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)

NOTE:
All persistent data are moved to KRS from the /opt/HPswsp/perset data file.
The vdsf is a link to the physical path of the device configured under HP LVM and dynamically points
to the next active path of the device (when the configured primary path fails and the system reboots).
All the Secure Path commands except autopath add command, supports vdsf as a command
argument and provides all the operations of Secure Path commands.
The vdsf is created under the /hpap/dsk/ directory for block device access, and under the /hpap/
rdsk/ directory for raw device access.
The vdsf is in the format of hpapX, where X is a positive integer starting from 0.
NOTE:
The persistence of vdsf associated with a LUN is lost, if the LUN, array, or an array type is deleted
from Secure Path's control. New vdsf is assigned when you add the deleted LUN back under Secure
Path’s control.
The autopath add <VDSF> command is not supported in this release of Secure Path.
ULM services
Secure Path uses the SCSI Upper Layer Module (ULM) interface to provide flexible configuration and
layering of modules above the SCSI disk drivers.
If you are configuring Secure Path into HP-UX 11i v1.0 64-bit operating systems and want it to coexist
with other pseudo drivers, register Secure Path with the ULM services for each LUN path you want
the Secure Path to control.
I/O load balancing
This section describes the following:
• Automatic failover
• Automatic path recovery
• Pro-active path monitor
Secure Path performs I/O load balancing while monitoring each path to ensure that the I/O transaction
is completed. The load balancing policy is selected by the administrator.
The I/O load balancing policy prevents any path from becoming overloaded, and it helps to prevent
the congestion that occurs when many I/O operations are directed to common devices along the
same path.
If a preferred path is used for a device, the entire I/O for that particular device flows through the
preferred path and no load balancing is done by Secure Path for that device.
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