Device backup and other availability solutions are chosen to balance the value of having information available against the cost of keeping that information available. Which of the following best describes fault-tolerant technologies?
A.
They are among the most expensive solutions and are usually only for the most mission-critical information.
B.
They help service providers identify appropriate availability services for the specific customer.
C.
They are required to maintain integrity, regardless of the other technologies in place.
D.
They allow a failed component to be replaced while the system continues to run.
Explanation:
A: Fault-tolerant technologies keep information available not only against individual storage device faults but even against whole system failures. Fault tolerance
is among the most expensive possible solutions for availability and is commonly justified only for the most mission-critical information. All technology will eventually
experience a failure of some form. A company that would suffer irreparable harm from any unplanned downtime can justify paying the high cost for fault-tolerant
systems.
+ B is incorrect because service-level agreements (SLAs) help service providers, whether they are an internal IT operation or an outsourcer, decide what type of
availability technology and service is appropriate. From this determination, the price of a service or the budget of the IT operation can be set. The process of
developing an SLA with a business is also beneficial to the business. While some businesses have performed this type of introspection on their own, many have
not, and being forced to go through the exercise as part of budgeting for their internal IT operations or external sourcing helps the business understand the real
value of its information.
+ C is incorrect because fault-tolerant technologies do not necessarily have anything to do with data or system integrity.
+ D is incorrect because “hot-swappable” hardware does not require shutting down the system and may or may not be considered a fault-tolerant technology. Hotswapping
allows the administrator to replace the failed component while the system continues to run and information remains available; usually degraded
performance results, but unplanned downtime is avoided.