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Quiz

2667 questions of the kind that actually get asked — in interviews, in architecture review boards, and by the person who has to run the thing at 3 AM. Every answer states the trade-off rather than the slogan, and says when the obvious choice is the wrong one.

All areas2667 Architecture Fundamentals81 Distributed Systems101 Data Architecture90 Cloud Architecture87 Networking86 API & Integration Architecture78 Reliability & Resilience88 Observability81 Performance & Capacity Engineering90 Security Architecture95 Cost Architecture & FinOps92 Business Architecture93 Architecture Communication91 Enterprise Architecture91 Legacy Modernization92 AI-Era Architecture86 Software Architecture & Engineering84 Architecture Patterns84 Architecture Decision-Making91 The Architect's Meta-Skills92 Delivery & Release Engineering93 Platform Engineering & Developer Experience92 Testing & Quality Architecture90 Data Platform Architecture88 Streaming & Real-Time Data93 Data Governance & Semantics81 Frontend & Experience Architecture91 Edge, Mobile & IoT88 Regulatory & Data Protection Architecture90 Assurance, Audit & Model Risk88
Difficulty Any beginner intermediate advanced

92 questions in Legacy Modernization.

  1. Migration Risk advanced

    Ant Group moved Alipay's core transaction data off a commercial relational database onto OceanBase, its own distributed database, beginning with a 1% slice in 2014 and reaching full replacement in 2019. What risk control is that ramp actually providing, and where would copying it be a mistake?

    3 min answer alibabaoceanbasealipayincremental-migration
  2. Migration Risk intermediate

    Review this migration plan. Cutover is staged by customer cohort at 2 percent then 10 then 50 then 100. Readiness for each step is "all automated tests green and no open P1 defects". The rehearsal ran against a 5 percent copy of production. The rollback step reads "restore from the pre-cutover snapshot if data integrity is compromised". What would you remove, what would you change, and what would you leave alone?

    3 min answer migration-riskcutoverabort-criteriarehearsal
  3. Migration Risk intermediate Multiple choice

    What is the single most important risk control in a migration, and why?

    2 min answer migration-riskreversibilityverificationblast-radius
  4. Migration Risk intermediate

    You want to replace a twelve-year-old monolith one capability at a time. The organisation releases that monolith once every six weeks on a Thursday evening, behind a change advisory board that meets fortnightly. Tell me what you would do first and why.

    3 min answer etsydeployment cadencestranglerchange advisory
  5. Modernisation Business Case intermediate

    A modernisation programme cannot get funded because its benefits are technical. How should the case be made?

    2 min answer gustobusiness-casefundingevidence
  6. Modernisation Business Case intermediate

    An architect must justify continued investment in a modernisation programme after eighteen months with the end state not yet reached. What should the argument be?

    2 min answer business-caseincremental-valueevidencesponsorship
  7. Modernisation Business Case advanced

    Make the case for modernising a system that works reliably and is expensive to change.

    2 min answer business-caseevidenceriskopportunity-cost
  8. Modernisation Business Case advanced

    You need funding for eighteen months of platform work with no customer-visible features. How do you build the case?

    1 min answer business-caseplatformfunding
  9. Parallel Run advanced

    A financial calculation engine is being replaced and the results must be proven equivalent before cutover. How should a parallel run be designed, and how are discrepancies triaged?

    3 min answer parallel-runmigrationreconciliationfinance
  10. Parallel Run advanced

    A logistics platform is replacing its core routing system. Should it run the old and new systems in parallel, and for how long?

    2 min answer delhiveryparallel-runverificationcutover
  11. Parallel Run intermediate

    An enterprise runs old and new systems in parallel to validate the replacement. What makes a parallel run effective, and what makes it expensive theatre?

    2 min answer parallel-runverificationcomparisoncutover
  12. Parallel Run advanced

    You are reimplementing a legacy capability. What does running old and new in parallel find that testing cannot?

    2 min answer parallel-runlegacyundocumented-behaviourtriage