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.

Put a CloudFront CDN in front to serve static assets from the edge — that offloads most of the traffic, so the origin can be much smaller across two AZs. Add a cache and make the database Multi-AZ with backups.

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

CloudFront

Networking

Enable CDN

System health

Erupting · SLA breach

/ 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.