Oracle RAC Build/Installation Prerequisites & Planning What prerequisites (OS packages, kernel parameters, network setup) are critical for an Oracle RAC installation? How do you configure shared storage (ASM, NFS, etc.) for RAC? What tools (e.g., asmca, crsctl) would you use? Installation Process Walk me through the steps to install Oracle RAC using Oracle Universal Installer (OUI). What role does the Grid Infrastructure (GI) play in a RAC environment? How does it differ from a standalone installation? Network Configuration Explain the purpose of SCAN (Single Client Access Name) listeners. How do they differ from regular listeners? How would you troubleshoot interconnect communication issues between RAC nodes? Post-Installation Checks What commands (e.g., crsctl, srvctl) would you use to verify the health of the cluster? How do you validate that all RAC nodes are functioning correctly and can access shared storage? ASM Integration How do you configure ASM disk groups for RAC? What redundancy levels (normal, high, external) are appropriate for different scenarios? What is the role of voting disks and OCR (Oracle Cluster Registry) in RAC? How would you back them up? Oracle RAC Patching & Upgrades Patch Types What is the difference between a PSU (Patch Set Update), CPU (Critical Patch Update), and a one-off patch? When would you use an OPatch auto rollback versus manual rollback? Rolling vs. Non-Rolling Patches Explain the process for applying a rolling patch to Oracle RAC. What components can be patched without downtime? How do you handle a non-rolling patch (e.g., Grid Infrastructure upgrade) in a RAC environment? Patching Workflow Walk through the steps to patch a RAC environment using OPatch. What pre-checks are mandatory? How do you verify that all nodes are running the same patch level post-update? Troubleshooting Patching Failures What logs would you check if a RAC patch fails during application (e.g., GI patching errors)? How do you resolve OPatch conflicts or missing dependencies during patching? Upgrade Strategies How would you plan a RAC database upgrade from 12c to 19c with minimal downtime? What are the risks of using DBUA (Database Upgrade Assistant) versus manual upgrades in a RAC environment? Troubleshooting RAC-Specific Issues Node Eviction & Split Brain What causes node evictions in RAC? How would you diagnose and resolve this? What is a "split-brain" scenario, and how does RAC prevent it? Performance in RAC How does "Global Cache Block Transfer" impact RAC performance? What wait events (e.g., gc cr block busy) would you monitor? What tools (AWR, ADDM) or views (GV$SESSION, GV$LOCK) do you use to diagnose RAC-specific performance issues? Clusterware Issues How do you troubleshoot OCR or voting disk corruption in RAC? What steps would you take if crsctl start crs fails on a RAC node? Situational/Scenario-Based Questions Disaster Recovery A RAC node crashes due to storage failure. How do you restore the cluster to full health? How would you rebuild a lost OCR file or voting disk in a live RAC environment? Scaling & Maintenance How do you add a new node to an existing RAC cluster? What steps are involved? Describe a time you performed a rolling maintenance task (e.g., OS patching) on a RAC cluster. High Availability How do you configure services in RAC to ensure workload balancing and failover? What is the role of FAN (Fast Application Notification) in RAC, and how does it integrate with applications? Advanced Topics RAC on Cloud/Exadata What unique considerations apply when deploying RAC on Oracle Exadata or OCI (Oracle Cloud Infrastructure)? How does RAC differ from Oracle Autonomous Database in terms of scalability and management? Security How do you enforce TDE (Transparent Data Encryption) in a RAC environment? What security best practices apply to RAC interconnect traffic? Automation How have you automated RAC provisioning or patching using tools like Ansible, Terraform, or OEM?