Episode 1. RAC. Day 1 of your 10 day sprint.

Welcome. This episode gives you the RAC story that proves 23 years of cluster depth. Listen once, then say the key lines out loud. That is the whole method: hear it, then say it.

First, the concepts in plain language. RAC is one database on many instances sharing storage. Cache fusion ships blocks across the interconnect instead of re-reading disk. The voting disk plus fencing decides who survives a split-brain. Services plus TAF decide where users reconnect after a node dies.

Say this sentence: RAC is not high availability without fencing and quorum, and TAF only helps if services are placed correctly.

Now the scenario. Payments slow down on one node, with gc cr block busy waits climbing. Understand: which service, which nodes, since when. Prepare: interconnect latency, CRS eviction logs, top wait event. Identify: interconnect saturation versus a hot block from bad partitioning; one hypothesis, then test. Support: rebalance the service, fix the partitioning, and write the runbook so the defect class cannot recur.

Say this bridge once, early in the interview. Say: In Oracle RAC I triage interconnect first and clusterware second, and on your CORE cloud layer I would apply the same order to the connectivity and observability signals.

Your Day 1 lab: walk a voting-disk failure drill on paper, then simulate a TAF service failover and narrate each step aloud.
Teaser: Tomorrow, Episode 2, DataGuard. Transport lag versus apply lag, and the switchover sentence you must not fumble.

Slow night node eviction drill. Pause this now and say the four steps out loud. Understand. Prepare. Identify. Support. Say it again. That repetition is the study.

Scenario two, quick rep. A node gets evicted weekly with no alert before it goes. Understand: eviction timestamps across CRS logs. Prepare: interconnect heartbeat history plus OS network drops. Identify: heartbeat loss from a flaky switch versus real load; test with ping history first. Support: fix the network path, add eviction alerting, document the stay-fixed monitor.

Close with your intro spine, first draft. I am a database integration engineer with twenty three years in production Oracle. Practice it until it is ninety seconds without notes.

Say the RAC sentence once more before bed: fencing plus quorum prevents split-brain. Done.