NOTE
Technical Planning for Software Systems
A methodology for technical planning: business goals, current bottlenecks, target architecture, risk reduction, migration stages, observability, and measurable outcomes.
This is a historical learning note and may contain outdated or incomplete understanding.
1. Technical Planning Is Not a Technology Wishlist
A roadmap should connect engineering work to a business or operational outcome:
- capacity headroom;
- reliability/SLO;
- developer velocity;
- cost;
- compliance/security;
- product capability.
2. Baseline the Current System
Document:
- architecture and ownership;
- traffic/data scale;
- incidents and recurring toil;
- latency/cost bottlenecks;
- dependency and deployment constraints.
Prioritize measured pain over fashionable infrastructure.
3. Define Target Properties
State measurable goals such as:
- p99 latency under X at Y QPS;
- recovery within Z minutes;
- database utilization below a threshold;
- deployment rollback within N minutes.
4. Work Backward into Capabilities
Map each target to technical work, then identify prerequisites and dependencies.
Prefer incremental milestones that leave the system usable after each stage.
5. Migration Is Part of the Design
For architecture changes define:
- compatibility period;
- dual-read/write or shadow traffic if needed;
- data backfill;
- validation metrics;
- rollback strategy;
- final cleanup.
A target architecture without a migration path is incomplete.
6. Revisit the Plan
Architecture is not a one-time five-year prediction. Review assumptions as traffic, organization, cost, and product needs change.