Multi-region cost blowout

expert

Scenario & brief

A team set the deployment footprint to active-active across two regions for a service whose SLA is only 99.95% availability — a level a single, well-built region hits comfortably. The result is double the cost and a blown budget (under $1,200/mo, p99 ≤ 140 ms, critical durability).

Bring it back to a single region done right — two AZs, a Multi-AZ database, add an ElastiCache and a CDN, Graviton on a Savings Plan — and resist expensive add-ons the SLA doesn't need.

6,000 rps peakp99 ≤ 140ms99.95% availdurability: criticalbudget $1,200/mo

Add components

Decide what this architecture actually needs — not every option belongs here.

App Servers

Compute

Instance class

Scaling

Instances (static)

6instances

Availability Zones

Purchasing

Deployment footprint

System health

Erupting · SLA breach

/ 100

Score

SLA not met yet

Monthly cost

$4,087

Budget $1,200/mo · $2,887 over

Metrics

Capacity57

Availability100

Durability25

Cost efficiency0

Requirements

Peak capacity — 21600 rps compute · 3400 rps db (need ≥ 6000 rps)
p99 latency — ~114 ms (need ≤ 140 ms)
Availability — 100.00% (need ≥ 99.95%)
Durability — at risk (need redundancy + backups)
Budget — $4087/mo (need ≤ $1200/mo)

Advisor

The database is saturated at peak — add a cache to shed read load, or scale it up.
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.