HP-UX System Administrator's Guide: Overview

on the functions of the failed server while the
original is repaired.
Persistent Device Special Files HP-UX 11i version 3 introduces a new type of
device special file called a persistent device special
file. Unlike legacy device special files
10
that
address devices by the hardware path to them,
persistent device special files use unique identifiers
built into (or associated with) supported devices to
address them. This means that multiple hardware
paths can be used to address the same device,
preventing single points of failure in interface
cards/slots.
Online Addition and Replacement Online Addition, Replacement, and Deletion
(OL*) is an HP-UX feature that allows for the
addition, replacement, and deletion of PCI /
PCI-X cards (adapters) while a system is running
(without requiring a reboot).
This feature enhances overall high-availability
since the system can remain active while an I/O
adapter is being added or replaced. When
combined with other high-availability products,
such as Serviceguard, system availability is
significantly improved.
Failed devices that support PCI OL*, if not critical
to your operation, can be replaced or removed.
Online Replacement suspends the driver instance
associated with the failed card and powers down
the slot so the card can be replaced with a new
one of the same type. Then power can be restored
to the slot and new card, and the driver resumed.
Online Deletion removes from the running kernel
the driver instance associated with the failed card
and powers down the slot so the card can be
removed. You can then (optionally) install a new
card of the same or different type using Online
Addition.
10. Legacy device special files are still supported in HP-UX 11i version 3 and can be used in conjunction
with persistent device special files.
Data Protection Tools 131