Trade-off Analysis
Making costs explicit and comparable rather than asserting a preference.
5 to work through
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intermediate
What distinguishes strong trade-off analysis from weak analysis in practice?
2 min answer -
advanced
A SaaS vendor's documented recovery posture is point-in-time restore for any individual data store. Atlassian's April 2022 incident tested it at scale - sites for 775 customers were deleted at once, no customer lost more than five minutes of data, and the last sites came back on 18 April. Which number had the organisation actually been buying, and what would you change first?
3 min answer -
advanced
Dropbox moved file storage off Amazon S3 onto its own infrastructure - Magic Pocket - completing the migration in 2016. What did that decision buy and what did it pay, and which facts about your own situation would have to be true before the same move is defensible?
3 min answer -
advanced
Product requires strong consistency and p99 latency under 100 ms for a globally distributed user base. Both are non-negotiable. What do you do?
2 min answer -
advanced
When Notion sharded its Postgres database in 2021 it created 480 logical shards spread across 32 physical instances, 15 per host. In 2023 it moved to 96 hosts with 5 logical shards each, keeping the same 480. What did the original choice buy, what did it cost, and what would you have had to believe to choose 32 logical shards instead?
3 min answer
2 terms in this topic
Build-Versus-Buy Crossover Point
The set of conditions under which operating a capability yourself beats paying a vendor - all of which must hold, because the standing cost of self-o…
conceptTrade-off Surface
The set of achievable combinations of competing qualities, on which improving one attribute necessarily costs another.
1 artifact you would hand over
Neighbouring topics
Meta-Skills
General material on how architects think and work.
Systems Thinking
Interactions and feedback loops rather than isolated components.
First-Principles Reasoning
Reducing to physics, mathematics and economics, then reasoning up.
Failure Thinking
Asking of every box and arrow how it fails and how you would know.
Constraint Thinking
Designing for the budget, skills and regulations that actually exist.
Pattern Recognition
Seeing a familiar problem, and checking whether the forces match.
Pragmatism
The simplest architecture that meets the requirements usually wins.
Judgement Under Uncertainty
Choosing the best worst case when information is missing.
Business Understanding
Connecting a design to the outcome that pays for it.
Influence Without Authority
Getting decisions adopted when you cannot mandate them.
Mentoring
Growing architectural judgement in other people.
Continuous Learning
Staying current without chasing every new thing.
Estimation
Sizing work and cost honestly, with the uncertainty stated.
Prioritisation
Choosing what not to do, and defending it.
Research & Evaluation
Assessing a technology quickly without adopting it by accident.
Handling Ambiguity
Making progress when the requirements are not yet knowable.
Technical Leadership
Setting direction and carrying accountability without a team reporting to you.
Ethics in Architecture
Privacy, accessibility, sustainability and the consequences of a design.
Career Development
Growing from senior engineer to architect and beyond.