The purpose of designing a resilient cluster is to ensure that your essential data and services are highly available. Setting up data and services as cluster resources allows them to be moved between nodes in the same cluster. This helps eliminate or minimize the downtime caused by a server failure or maintenance.
You can determine what data and services to set up as cluster resources by asking and answering the following questions:
What are the key services that drive your business?
What services are essential for business continuance?
What is the cost of downtime for the essential services?
Based on their mission-critical nature and cost of downtime, what services are the highest priority for business continuance?
What data is necessary to support the highest-priority services?
How much data is involved, and how important is it?