Web traffic roughly doubles every weekday at noon and halves overnight, but the exact level varies. The architecture must maintain response times without paying for permanent peak capacity. Which approach is most appropriate?
A.Fixed fleet sized for peak
Peak-sized fleets pay for unused capacity most of the day.
B.EC2 Auto Scaling with target tracking on average CPU/load plus scheduled scaling for known peaks
Correct. Target tracking handles variance; scheduled scaling handles the predictable noon surge.
C.Manually resize instances each morning
Manual daily resizing is slow, error-prone, and cannot react to variance.
D.Move everything into a single large instance
One large instance caps scale and creates a single point of failure.
Why this answer
Target-tracking scaling adjusts capacity automatically against a metric (e.g., average CPU or ALB request count), while scheduled scaling pre-warms known recurring peaks — elastic capacity that tracks demand without paying for peak 24/7.
Correct answer: B · Last reviewed 2026-10-25
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