Which AWS design approach best delivers HIGH AVAILABILITY — minimizing downtime when a single component fails?
A.One large instance in a single Availability Zone
Single instance + single AZ = maximum failure exposure.
B.Multiple instances across multiple Availability Zones behind a load balancer
Correct. Redundancy across AZs is the textbook HA pattern.
C.A nightly backup to S3
Backups restore after failure — they don't prevent downtime.
D.Vertical scaling of a single server
Scaling up still leaves one point of failure.
Why this answer
High availability = redundancy across failure domains. Multi-AZ + load balancer keeps serving when one AZ or instance dies. Backups enable recovery (DR), not availability; a single instance — however big — is a single point of failure.
Correct answer: B · Last reviewed 2026-10-27
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