Search the practice set
126 questions, 454 terms and 400 topics in 20 areas.
60 results for “Total Cost of Ownership”
Total Cost of Ownership
The full lifetime cost of a capability, including the people, operations, upgrades and exit that a licence comparison leaves out.
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.
Tagging Strategy
A defined, enforced set of metadata labels applied to every resource, without which cost allocation, ownership and lifecycle automation are all impossible.
Architecture Cost Model
A calculation, made during design, of what an architecture will cost to run at expected and at peak volume.
Cost per Request
The fully-loaded infrastructure cost of serving one request, and the unit that makes architectural cost decisions comparable.
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.
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.
AI Gateway
A shared proxy in front of model providers that centralises routing, keys, quotas, caching, logging and safety policy.
Account Vending
Automated creation of new cloud accounts pre-configured with the organisation's networking, identity, logging, guardrails and cost allocation.
Application Portfolio Management
Maintaining an inventory of every application with its owner, cost, business value and technical health, and using it to decide what to invest in, replace or retire.
Burstable Instance
An instance that provides a low baseline CPU allocation and accrues credits while idle, spendable for short periods of full performance.
Capability Map
A structured view of everything a business does, used as the stable frame for mapping applications, investment, ownership and gaps.
Cardinality
The number of distinct time series produced by a metric, which is the product of the distinct values of all its labels — and the main driver of monitoring cost.
Cascading Timeout
The effect of independently-chosen per-hop timeouts summing to a total far longer than any caller is willing to wait.
Chargeback and Showback
Attributing cloud cost to the teams that generate it — either informationally (showback) or by moving it onto their budget (chargeback).
Cloud Pricing Models
The purchase options for cloud compute — on-demand, committed use, and spot — which differ by up to 90% for identical hardware.
Cognitive Load
The total amount a team must hold in its head to work effectively, and a real constraint on how many services or domains one team can own.
Context Window
The maximum number of tokens a model can attend to in one request, holding the system prompt, history, retrieved context, tools and the answer.
Cross-Zone Data Transfer
Charges incurred when data moves between availability zones within a region — invisible on architecture diagrams and a recurring surprise on cloud bills.
Cross-Zone Load Balancing
Whether a load balancer node distributes traffic to targets in all zones or only its own — a setting that affects both balance and data transfer cost.
Data Contract
An explicit, versioned, enforced agreement between a data producer and its consumers about schema, semantics, quality and change policy.
Data Mesh
An organisational approach that gives domain teams ownership of their analytical data as a product, with a self-serve platform and federated governance.
Data Retention Policy
A defined rule for how long each class of data is kept, where, and what happens at the end of it.
Database Index
A secondary structure that lets the engine find rows without scanning, trading write cost and storage for read speed.
Database per Service
Each service owning its own datastore, with no other service reading or writing it directly.
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.
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,
A service calls four dependencies. How do you size its thread pools, and why is the total often smaller than people expect?
The sizing rule Little's Law, per dependency: concurrency = throughput to that dependency × its latency. Dependency Calls/s Latency Concurrency Pool Auth 500 10
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
Security wants mandatory hardware keys for every login; the business says it will cost conversions. How do you resolve it architecturally rather than by picking a side?
What the interviewer is testing Whether you treat security as a fixed dial to be turned up, or as a risk proportionate design variable. Both stated positions ar
You inherit an estate of roughly 400 applications, no reliable inventory, and a mandate to reduce cost and risk. What do you do in the first ninety days?
What the interviewer is testing Whether you can sequence work at portfolio scale, and whether you go for evidence before strategy. This is the enterprise archit
Your services currently trust anything inside the VPC. A security review says move to zero trust. What changes, and what will it cost you?
What the interviewer is testing Whether "zero trust" is a concrete set of changes to you, or a slogan. What actually changes Workload identity. Every service ge
A dashboard has been wrong for three weeks. Nobody knows which upstream produced the table it reads. What is the governance failure, and what fixes it?
The failures, and there are three 1. No lineage. The question "which upstream produced this?" should be answerable in seconds by following a derived dependency
A team wants to build a new internal API on serverless functions. It will serve steady traffic of about 200 requests per second during business hours. What do you advise?
What the interviewer is testing Whether you can apply the serverless trade off to a specific workload rather than treating it as a default good or a default bad
Total Cost of Ownership
Lifetime cost including people, operations, upgrades and exit.
Application Portfolio Management
Inventory, ownership, cost and health for every application.
AI Cost Management
Token accounting, routing, caching and the context-window budget.
Architecture Cost Modelling
Pricing a design before building it, at expected and at ten times volume.
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.
Cost vs Reliability
Each nine costing an order of magnitude, and pricing the failure instead.
Observability Cost
Telemetry bills, cardinality control and retention tiering.
Performance vs Cost
Buying latency, and knowing what the last millisecond is worth.
Telemetry Cost
Observability bills that rival compute, and where to cut without going blind.
AI Observability
Logging prompts, versions, retrieved context and cost per request.
APIs as Products
Ownership, lifecycle, deprecation policy and developer experience.
Build vs Buy
Differentiation, five-year TCO, and the exit cost of each option.
Capability Maps in EA
The stable frame for hanging investment, ownership and health off.
Cloud Governance
Preventive policy, tagging, quotas and cost and security guardrails.
Cloud Pricing Models
On-demand, committed and spot, and the crossover arithmetic.
Competing Consumers
Scaling throughput with instances, at the cost of ordering.
Compute Optimisation
Instance families, utilisation, and architecture that wastes less.
Consensus Protocols
Raft, Paxos and quorums — what they guarantee and what they cost.
Data Governance
Ownership, lineage, quality, catalogues and who may see what.