Fundamentals and Core Concepts
What this section covers
Note: the official blueprint for this exam is unverified. The material below covers transferable principles that question writers draw on, but confirm vendor-specific terminology against the official guide.
Start with the vocabulary that every later domain reuses. A service model (IaaS, PaaS, SaaS) shifts the boundary of who manages the stack; questions usually hinge on which layer the customer still owns (patching the guest OS vs patching the hypervisor). Elasticity is automatic, demand-driven capacity change; scalability is the ability to grow at all - horizontal (out) versus vertical (up). High availability minimizes downtime; fault tolerance keeps working through a component failure with no interruption; durability protects data from loss. RTO is how long recovery may take; RPO is how much data you may lose, measured backward from the failure. Know control plane vs data plane, stateless vs stateful components, and the basic performance pair latency vs throughput.
Traps
- Confusing backup with replication: replication faithfully copies corruption and deletions.
- Treating "scalable" as a synonym for "fast".
- Answering with a technology when the question asks for a definition or first step.
- "Most" and "best" qualifiers - re-read the constraint (cost, time, effort) before choosing.
Worked example
A business says: "We can tolerate six hours of downtime but no more than 15 minutes of lost transactions." RTO = 6 hours; RPO = 15 minutes. That instantly rules out nightly-only backups for the data tier (24-hour RPO gap) while permitting a slower, cheaper failover for the compute tier. Rule of thumb: derive requirements from the sentence, then eliminate options that violate the stricter of the two numbers.