When designing high availability for an Oracle RAC (Real Application Clusters) database deployed on OCI Exadata Database Service, which THREE architectural characteristics ensure fault tolerance and uptime? (Choose three.)
Spreading RAC nodes across distinct Fault Domains or Availability Domains isolates each instance from a single hardware or datacentre failure, so surviving nodes continue serving the database. This directly satisfies the fault-tolerance and uptime requirement by removing any single point of failure at the infrastructure layer.
Why this answer
Option C is correct because Oracle RAC achieves fault tolerance by distributing cluster nodes across distinct Fault Domains or Availability Domains, so the failure of one domain does not take down the entire database. Option D is correct because Application Continuity and Transparent Application Failover (TAF) mask instance or node failures by replaying or failing over in-flight sessions, preserving application uptime during outages. Option E is correct because Exadata Storage Cells use Exadata Smart Flash Cache and ASM redundancy across multiple Storage Servers, so a failed cell does not cause data loss or database downtime.
Option A is wrong because a single Oracle Linux instance without Grid Infrastructure cannot form a RAC cluster and provides no node-level redundancy. Option B is wrong because a single local NVMe drive on one node is a single point of failure and is not shared clustered storage, which RAC requires.
Exam trap
The trap is confusing 'high availability' with 'backup' or 'performance' — candidates may pick options that sound resilient (single powerful node) but actually remove redundancy, missing that HA requires eliminating every single point of failure across compute, storage, and sessions.