This document describes the Dynamic Root Disk (DRD) toolset,
which you can use to perform software maintenance and recovery on
an HP-UX operating system with minimum system downtime. DRD enables
you to easily and safely clone a system image from a root disk to
another disk on the same system.
Using DRD commands, you can perform software maintenance or
make other modifications on the cloned system image without affecting
the active system image. When ready, you can boot the cloned image
on either the original system or a different system. The only downtime
required for this process is while the system reboots.
Hewlett-Packard developed DRD to minimize the usual maintenance
window during which you shut down the system to install patches. With
DRD, the system keeps running while you clone the system image and
apply patches to the cloned image. DRD tools can manage the two system
images simultaneously. DRD also provides a fail-safe mechanism for
returning the system to its original state, if necessary.
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