Introduction to NonStop Operations Management

Contingency Planning
Introduction to NonStop Operations Management–125507
10-12
Determining Which Type of Backup Site Best Meets
Your Needs
Table 10-1. Backup-Site Alternatives: Advantages and Disadvantages (page 1 of 2)
Backup Site Advantages Disadvantages
Cold Site Inexpensive way to acquire or
lease a second computer site.
No equipment or operating costs
until a disaster occurs.
Can require 20 days or more to
become operational. Everything
from furniture to computers must be
ordered, delivered, and installed.
Acquiring hardware during an
emergency might be difficult.
It is difficult to test a recovery plan
within defined time periods.
When leasing a cold site, there is a
risk of contention for use of the
facility or hardware in the event that
a widespread disaster affects other
companies under contract for the
same site. There are restrictions on
how long a tenant can use the cold
site.
Operational-
Ready Site
System and site are in a ready
state.
Security is in the control of one
company.
Simplifies recovery-plan testing.
If the system is large and is not part
of a network, ensuring database
consistency with the primary site
requires time and adversely affects
the primary system’s availability and
response time.
Data-Ready Site System and site are in a ready
state.
Security is in the control of one
company.
Simplifies recovery-plan testing.
Less expensive than an online-
ready site.
Data is only as current as the latest
backup. There is a risk of losing
data from transactions on the
primary system that have not been
restored to the data-ready systems.
Online-Ready
Site
Recovery occurs within an hour,
with no loss of data or
transactions.
Normal database backup can be
shared among nodes, thus
minimizing the burden on any one
system.
Simplifies recovery-plan testing.
Practical only for companies with
multiple computer sites.
More expensive than most of the
other alternatives.