Cost vs Reliability
Each nine costing an order of magnitude, and pricing the failure instead.
5 to work through
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advanced
A cost-sensitive platform must choose between a highly available architecture and a cheaper one with a wider failure domain. How should the decision be made?
2 min answer -
advanced
A team is asked to reduce infrastructure cost by 30%. How do you make the reliability trade-off explicit rather than accidental, and what should be cut first?
2 min answer -
advanced
One architecture has excellent performance and mediocre reliability; another is reliable at substantially higher cost. How should the trade-off be evaluated?
2 min answer -
advanced
To cut 45% from database spend a team moved the primary from a synchronous two-zone pair to a single zone, with snapshots every 30 minutes and log shipping every 5. The zone never fails. It gets slow - storage latency goes from 1 ms to 80 ms and stays there for two hours. What happens, minute by minute?
3 min answer -
advanced
What would it cost to move a service from 99.9% to 99.99% availability, and how would you decide whether it is worth it?
2 min answer
2 terms in this topic
Cost of Downtime
The quantified business impact of unavailability per unit of time, which converts reliability investment from an argument into an arithmetic comparison.
conceptCost versus Reliability
Reliability is bought with redundancy and headroom, both of which cost money — so the target must be chosen rather than assumed.
Neighbouring topics
Cost & FinOps
General material on the economics of an architecture.
Total Cost of Ownership
Lifetime cost including people, operations, upgrades and exit.
Cloud Pricing Models
On-demand, committed and spot, and the crossover arithmetic.
Reserved & Committed Capacity
Committing the baseline, laddering terms, and expiry as a silent failure.
Spot & Interruptible Capacity
Deep discounts for work that can be interrupted and resumed.
Unit Economics
Cost per request, per tenant, per transaction — the actionable number.
Cost per Request
Fully-loaded per-unit cost, including the lines usually left out.
Storage Costs
Tiering, lifecycle policies, retrieval charges and minimum durations.
Network & Egress Costs
Cross-zone and cross-region transfer that appears on no diagram.
Compute Optimisation
Instance families, utilisation, and architecture that wastes less.
Rightsizing
Matching provisioned resources to observed demand rather than to a guess.
Cost Allocation
Tagging enforced at provisioning, and apportioning shared costs.
Showback & Chargeback
Making teams see, or own, the cost of what they run.
Architecture Cost Modelling
Pricing a design before building it, at expected and at ten times volume.
Observability Cost
Telemetry bills, cardinality control and retention tiering.
Licence & Vendor Costs
Per-core, per-seat and per-environment terms that shape designs.
FinOps Practice
Inform, optimise, operate — and cost as a design-review criterion.
Waste Elimination
Idle environments, orphaned volumes, forgotten instances, dead data.
Cost Governance
Budgets, anomaly alerts, quotas and preventive policy.