MushyBook
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Tune the data tier

intermediate

Scenario & brief

A service peaking at 5,000 rps is bottlenecked entirely at the data tier: it runs a burstable db.t3.medium, no cache, single-AZ, no backups. Queries are queueing and any failure loses data.

Targets: p99 ≤ 140 ms, 99.95% availability, critical durability, under $1,000/mo.

5,000 rps peakp99 ≤ 140ms99.95% availdurability: criticalbudget $1,000/mo

App Servers

Compute

3instances

System health

Erupting · SLA breach

28

/ 100

Score

SLA not met yet

Monthly cost

$492

Budget $1,000/mo · within budget

Metrics

Capacity7
Availability30
Durability25
Cost efficiency80

Requirements

  • Peak capacity — 5400 rps compute · 350 rps db (need ≥ 5000 rps)
  • p99 latency — ~174 ms (need ≤ 140 ms)
  • Availability — 99.00% (need ≥ 99.95%)
  • Durability — at risk (need redundancy + backups)
  • Budget — $492/mo (need ≤ $1000/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.