HP 3PAR HP-UX Implementation Guide

HP Support Center
• the HP 3PAR Command Line Interface Administrator’s Manual, “Using Persistent Ports for
Nondisruptive Online Software Upgrades”
This document is available on the HP SC website:
HP Support Center
Fibre Channel
HP 3PAR OS Persistent Ports feature Setup and Connectivity Guidelines for FC
Starting with HP 3PAR OS 3.1.2, the HP 3PAR OS Persistent Ports feature is supported for FC
target ports.
Starting with HP 3PAR OS 3.1.3, the Persistent Ports feature has additional functionality to minimize
I/O disruption during an array port “loss_sync” event triggered by a loss of array port connectivity
to fabric.
Specific cabling setup and connectivity guidelines need to be followed for HP 3PAR OS Persistent
Ports to function properly:
• HP 3PAR StoreServ Storage FC partner ports must be connected to the same FC Fabric and
switch.
• The FC fabric being used must support NPIV, and NPIV must be enabled.
• The host–facing HBAs must be configured for point-to-point fabric connection (there is no
support for direct-connect “loops”).
HP-UX Persistent Ports Limitations
HP-UX 11i v2 builds the hardware path of a storage device using the N_port ID that is assigned
by the attached fabric. Due to this dependence, HP-UX 11i v2 does not take advantage of the HP
Persistent Ports feature. When a persistent port fails over to its partner port and changes its N_port
ID, the operating system detects the original path as failed. If PVLinks is configured properly, I/O
is redirected to an alternate target link. When the original array port recovers and failback occurs,
PVLinks switches I/O to its original path.
NOTE: When a persistent port fails over to its partner port and changes its N_port ID, the
operating system will create a new legacy DSF. The new legacy DSF will initially be in the CLAIMED
state, but when the port fails back to the original path, it will change to the NO_HW state. You
can remove the stale DSFs by using the following command:
# rmsf -H <hw_path>
For example:
# rmsf -H 0/0/0/9/0/0/0.50.100.0.2.5.0
HP recommends that PVLinks multipathing be enabled on all HP-UX 11i v2 host servers in order to
avoid I/O disruption when a persistent port fails over to its partner port.
Setting Up and Zoning the Fabric 13