Installation guide

Fault Tolerant Design
HP-UX version 11.00.03 Getting Started 1-7
■ Continuum systems contain multiple fans and environmental monitoring
features. Power and air flow information is collected automatically and
corrective actions are initiated as necessary.
Continuous Availability Software
The fault tolerant software features include the following:
■ Stratus provides a layer of software fault tolerant services with the standard
HP-UX operating system. These services constantly monitor for and respond
to hardware problems. The fault tolerant services are below the application
level, so applications do not need to be customized to support them.
■ The fault tolerant services software automatically maintains
mean-time-between-failures (MTBF) statistics for many system components.
Administrators can access this information at any time and can reconfigure the
MTBF parameters that affect how the fault tolerant services respond to
component problems.
■ The Remote Service Network (RSN) allows Stratus to monitor and service
your system at any time. The RSN automatically transmits status information
about your system to the Customer Assistance Center (CAC) where trained
personnel can analyze and correct problems remotely. (CAC services require
a service contract.)
■ The console command interface provides a set of console commands that let
you quickly control key machine actions.
■ The fault tolerant services software provides special utilities that help you
monitor and manage the fault tolerant hardware resources. These utilities
include addhardware, ftsmaint, and several flash card and RSN utilities.
■ The logical volume manager (LVM) utilities let you create logical volumes,
mirror disks, backup data, and perform other services to maximize
data-storage flexibility and integrity. The LVM utilities are part of the
standard HP-UX operating system.
Duplexed Components
Most physical components in a Continuum system can be configured redundantly
to maintain fault tolerance. The redundancy method might be full duplexing
(lock-step operation), logical pairing (online/standby), or some method of
pooling. All systems contain the following fault tolerant features:
■ boards/cards—Most boards or cards in the system can be paired in some way.
Pairing methods include full duplexing (for example, CPU/memory), logical
pairing (for example, console controller and DPT boards), or dual initiation of