Integrating multiple systems can increase chances of single failure
and could cause access to an entire supply chain to be unavailable.
To implement databases that are highly available, you must design an infrastructure
that can mitigate downtime, such as by deploying redundant hardware. You must
also embrace techniques that allow recovery from disasters, such as by implementing
appropriate backup routines.
Measuring and Planning Availability
Most organizations initially assume that they need data access 24/7, meaning that
the system must be available 24 hours a day, 7 days a week. Quite often, this requirement
is stated with little examination of the business functions the system must
support. As the cost of technology components declines and reliability increases,
many feel that achieving very high levels of availability should be simple and cheap.
Unfortunately, while many components are becoming cheaper and more reliable,
component availability doesn??™t equate to system availability. The complex layering of
hardware and software in today??™s two- and three-tier systems introduces multiple
interdependencies and points of failure.
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