MushyBook
All challenges

Offload static traffic with a CDN

beginner

Scenario & brief

A largely-static site serves 6,000 rps — but almost all of it is images, CSS, and JS being served straight from the origin fleet, which has been scaled up to cope in a single AZ.

Targets: p99 ≤ 150 ms, 99.9% availability, standard durability, under $700/mo.

6,000 rps peakp99 ≤ 150ms99.9% availdurability: standardbudget $700/mo

CloudFront

Networking

System health

Erupting · SLA breach

28

/ 100

Score

SLA not met yet

Monthly cost

$1,050

Budget $700/mo · $350 over

Metrics

Capacity28
Availability30
Durability25
Cost efficiency30

Requirements

  • Peak capacity — 10800 rps compute · 1700 rps db (need ≥ 6000 rps)
  • p99 latency — ~135 ms (need ≤ 150 ms)
  • Availability — 99.00% (need ≥ 99.90%)
  • Durability — at risk (need backups)
  • Budget — $1050/mo (need ≤ $700/mo)

Advisor

  • The database is saturated at peak — add a cache to shed read load, or scale it up.
  • Compute runs in a single AZ — spread across ≥2 AZs (with ≥2 instances) to meet the availability target.
  • The database has no Multi-AZ standby or replica — a failure risks data loss. Enable Multi-AZ and backups.

Discussion

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For learning purposes only. Costs and capacities are illustrative, not live AWS prices. Not affiliated with or endorsed by Amazon Web Services.