If you're planning on taking the Security+ exam, you should have a good understanding of failover clusters and how they provide high availability for a service offered by a server. For example, can you answer this question?
Q. Your organization hosts a web site with a back-end database server. During a recent power outage, the server crashed, resulting in a significant amount of lost data. Which of the following can your organization implement to prevent this loss from occurring again?
B. Disaster recovery procedures
C. Warm site
D. Higher RTO
More, do you know why the correct answer is correct and the incorrect answers are incorrect? The answer and explanation is available here.