Search the practice set
126 questions, 454 terms and 400 topics in 20 areas.
60 results for “Performance vs Cost”
Cost vs Reliability Trade-off
The non-linear relationship between availability and spend, which makes each additional nine roughly an order of magnitude more expensive.
Build vs Buy
The choice between developing a capability in-house and acquiring it, decided on differentiation and total cost rather than on feature lists.
Horizontal vs Vertical Scaling
Adding more machines versus making one machine bigger — and the fact that vertical is underrated for stateful tiers.
Managed vs Self-Managed
Trading control, portability and unit cost against the operational burden of running the thing yourself.
Provisioned vs Serverless Capacity
Paying for a fixed database size continuously, versus paying for capacity consumed with automatic scaling — a crossover decision driven by duty cycle.
Total Cost of Ownership
The full lifetime cost of a capability, including the people, operations, upgrades and exit that a licence comparison leaves out.
Burstable Instance
An instance that provides a low baseline CPU allocation and accrues credits while idle, spendable for short periods of full performance.
Database Index
A secondary structure that lets the engine find rows without scanning, trading write cost and storage for read speed.
Denormalisation
Deliberately duplicating data across records to make reads cheap, accepting the write-time cost of keeping copies in step.
Dropbox's Move Off S3
Dropbox moved the majority of its file storage off Amazon S3 onto custom infrastructure, reporting savings that its S-1 filing put at roughly $75 million over two years.
Indexing Strategy
Choosing the set of indexes a table carries by working backwards from its actual queries, and accepting the write cost that each one adds.
Well-Architected Review
A structured self-assessment of a workload against defined pillars — operational excellence, security, reliability, performance, cost, and sustainability.
Active-Active vs Active-Passive
Whether all regions serve traffic simultaneously, or one serves while another waits to take over — a choice about which failure mode you would rather have.
Application Performance Monitoring
Instrumentation inside the application that attributes latency and errors to specific code paths, queries and dependencies.
Architecture Cost Model
A calculation, made during design, of what an architecture will cost to run at expected and at peak volume.
Containment vs Eradication
Stopping an attacker's ongoing access versus removing their foothold entirely — sequential phases with different urgency and different risks of doing them wrong.
Cost per Request
The fully-loaded infrastructure cost of serving one request, and the unit that makes architectural cost decisions comparable.
Delivery vs Maintainability
Choosing where to take deliberate shortcuts, based on which kinds of debt are cheap to repay and which compound.
Durability vs Availability
Two different storage guarantees — whether data survives, and whether it can be reached right now — routinely conflated because both are quoted in nines.
ETL vs ELT
Whether data is transformed before loading into the target or after it, which decides where the compute happens and how much raw history you keep.
Egress Cost
The charge for moving data out of a cloud provider or across its zones and regions — usually the least-anticipated line on a cloud bill.
Fail-Fast vs Fail-Safe
Whether a component should stop immediately on detecting a problem, or continue in a degraded but safe mode — a choice that depends entirely on which outcome is worse.
Layer 4 vs Layer 7 Load Balancing
Balancing on connection metadata (IP and port) versus on the content of the request (path, host, headers).
Monolith vs Microservices
A trade of deployment independence against distributed-systems complexity, decided by team topology far more often than by technology.
OLTP vs OLAP
Two workload shapes with opposite requirements — many small indexed transactions versus few large scans and aggregations — which is why they belong in different stores.
Operational vs Analytical Store
The separation between the store serving the application's transactions and the one serving reporting and analysis, and the mechanism connecting them.
Re-architect vs Rebuild
Restructuring an existing system incrementally versus writing a replacement from scratch — and the strong evidence that incremental wins.
A design review presents a new event-driven platform. What cost questions do you ask before approving it?
What the interviewer is testing Whether cost is part of your architecture review or an afterthought handled by finance later, and whether you know the specific
A fleet of 200 instances averages 15% CPU and 85% memory. Finance wants a 40% cost reduction. What do you do?
The diagnosis The instance family is wrong. 15% CPU and 85% memory means the workload is memory bound running on general purpose or compute optimised instances,
Prime Video reported a 90% cost cut by consolidating a serverless distributed service into one process. Does that mean microservices were the wrong choice, and what is the actual decision rule?
What actually happened The Prime Video Video Quality Analysis team's 2023 post describes an audio/video monitoring service built as Step Functions orchestrating
Performance vs Cost
Buying latency, and knowing what the last millisecond is worth.
Cost vs Reliability
Each nine costing an order of magnitude, and pricing the failure instead.
Build vs Buy
Differentiation, five-year TCO, and the exit cost of each option.
Horizontal vs Vertical Scaling
Scale out for stateless, scale up first for stateful.
Managed vs Self-Managed
Trading control and unit cost against operational attention.
Strong vs Eventual Consistency
A per-operation decision, resolved by what a stale read would cost.
AI Cost Management
Token accounting, routing, caching and the context-window budget.
Application Performance Monitoring
Attributing latency to code paths, queries and dependencies.
Architecture Cost Modelling
Pricing a design before building it, at expected and at ten times volume.
Build vs Buy
Differentiation versus table stakes, priced over five years.
Caching for Performance
Layer choice, hit ratio as a first-class metric, and cold-cache recovery.
Centralised vs Distributed
Shared platform leverage against team autonomy.
Cost & FinOps
General material on the economics of an architecture.
Cost Allocation
Tagging enforced at provisioning, and apportioning shared costs.
Cost Governance
Budgets, anomaly alerts, quotas and preventive policy.
Cost per Request
Fully-loaded per-unit cost, including the lines usually left out.
Database Performance
Plans, indexes, contention and the pool in front of the database.
Delivery vs Maintainability
Fast in the cheap places, careful in the expensive ones.
Functional vs Non-Functional
Behaviour versus quality of behaviour, and why only the second constrains structure.
Layer 4 vs Layer 7
Connection-level versus request-level balancing, and what each unlocks.
Monolith vs Microservices
A team-topology decision far more often than a technology one.
Network Performance
Latency floors, bandwidth-delay product, and what no code change fixes.
Network Performance Tuning
Keep-alive, compression, payload size and round-trip elimination.
Observability Cost
Telemetry bills, cardinality control and retention tiering.
Orchestration vs Choreography
A coordinator that knows the flow, or services that react to events.
Performance & Capacity
General material on performance and capacity engineering.
Performance Budgets
Targets enforced in CI so regressions fail the build.
Rebuild vs Re-architect
Why greenfield replacement fails, and the narrow cases where it does not.