Recovery" is the term used for the process of restoring a computer installation
to operational status after all or most of it has been destroyed by some
disaster. The three essential components of successful disaster recovery
are: the computer installation's data, the computer installation's hardware,
and a properly defined and detailed Disaster Recovery procedure.
Data for Disaster Recovery is a complete and current backup copy of the
computer installation's data. Such a backup copy often called a "vault"
copy, so named because this copy of the data is typically stored securely
in some sort of a vault, a significant distance away from the computer
installation. The production of current vault data is a non-trivial process
and requires much planning. Data Vaulting is described elsewhere on this
Hardware for Disaster Recovery is, in most instances, a subset of the
main installation's hardware located at another facility that is a significant
distance from the main installation. Because only a subset of the primary
hardware is usually available at the DR site, a mapping of applications
to machines and to resources is required in order to make rapid recovery
from a disaster.
C. A Disaster Recovery Plan is a comprehensive document that defines such
a mapping of applications to hardware. It is, in fact, a detailed series
of instructions of precisely what to do in the event of a disaster. As
part of the DR plan are "action envelopes" or directives to individuals
that will be instrumental in effecting recovery. Procedures for transporting
the Vault data to the DR site, the booting and initialization of machines,
the running of applications, and a chronological ordering of all these
steps including contingencies is part of the DR Plan.