Open Questions and Estimation Log

This page tracks open discovery questions that should be answered before locking Phase 2/3 architecture choices.

Status values:

• Open
• In progress
• Answered
• Needs measurement

Response fields to fill for each question:

• Status (Open/In progress/Answered/Needs measurement): Open
• Notes:

A) User Workflow and Product Expectations

1. What is an acceptable time-to-first-insight for a typical user run?

   • Status (Open/In progress/Answered/Needs measurement): Open
   • Notes:

2. What is an acceptable total turnaround time for small, medium, and large simulations?

   • Status (Open/In progress/Answered/Needs measurement): Open
   • Notes:

3. Which intermediate results are most valuable to users during RUNNING status?

   • Status (Open/In progress/Answered/Needs measurement): Open
   • Notes:

4. How much partial-result staleness is acceptable (for example 10 s vs 60 s)?

   • Status (Open/In progress/Answered/Needs measurement): Open
   • Notes:

5. Do users prefer fewer high-confidence updates or frequent best-effort updates?

   • Status (Open/In progress/Answered/Needs measurement): Open
   • Notes:

6. Which user personas need queue predictions versus detailed task-level telemetry?

   • Status (Open/In progress/Answered/Needs measurement): Open
   • Notes:

B) HPC Connectivity and Queue Characteristics

7. What is the typical time needed to connect to target HPC clusters (for example Ares)?

   • Status (Open/In progress/Answered/Needs measurement): Open
   • Notes:

8. What is the p50/p95 time jobs spend in HPC waiting queues by partition/class?

   • Status (Open/In progress/Answered/Needs measurement): Open
   • Notes:

9. How often do HPC connection/setup failures occur, and what are top failure modes?

   • Status (Open/In progress/Answered/Needs measurement): Open
   • Notes:

10. Are there cluster-side limits that strongly affect orchestration design (rate limits, job caps, walltime constraints)?

    • Status (Open/In progress/Answered/Needs measurement): Open
    • Notes:

11. Which queue-delay patterns are predictable enough to model in UI ETA messaging?

    • Status (Open/In progress/Answered/Needs measurement): Open
    • Notes:

C) Parallelism and Concurrency Demand

12. How many parallel tasks per simulation do users typically want on HPC?

    • Status (Open/In progress/Answered/Needs measurement): Open
    • Notes:

13. What is the upper bound users realistically request for tasks per simulation?

    • Status (Open/In progress/Answered/Needs measurement): Open
    • Notes:

14. How many simulations in parallel does a single user expect to run?

    • Status (Open/In progress/Answered/Needs measurement): Open
    • Notes:

15. How many concurrent active users should the system support in normal and peak periods?

    • Status (Open/In progress/Answered/Needs measurement): Open
    • Notes:

16. What fairness model is expected when concurrent user demand exceeds capacity?

    • Status (Open/In progress/Answered/Needs measurement): Open
    • Notes:

D) Result Shape and Data Volume

17. How long does it take to dump a single binary result artifact to disk (p50/p95)?

    • Status (Open/In progress/Answered/Needs measurement): Open
    • Notes:

18. How many result files are produced per simulation for each supported simulator?

    • Status (Open/In progress/Answered/Needs measurement): Open
    • Notes:

19. How many pages are typically present per result file?

    • Status (Open/In progress/Answered/Needs measurement): Open
    • Notes:

20. What are typical and worst-case per-page array sizes?

    • Status (Open/In progress/Answered/Needs measurement): Open
    • Notes:

21. What are typical and worst-case merged-result payload sizes?

    • Status (Open/In progress/Answered/Needs measurement): Open
    • Notes:

22. Which result subsets are most frequently viewed first by users?

    • Status (Open/In progress/Answered/Needs measurement): Open
    • Notes:

E) Reliability, Recovery, and Operations

23. What data loss tolerance is acceptable for task progress updates?

    • Status (Open/In progress/Answered/Needs measurement): Open
    • Notes:

24. Is at-least-once or exactly-once semantics required for final result persistence?

    • Status (Open/In progress/Answered/Needs measurement): Open
    • Notes:

25. What recovery time objective is acceptable after transient broker/network outages?

    • Status (Open/In progress/Answered/Needs measurement): Open
    • Notes:

26. Which retries should be automatic versus operator-controlled?

    • Status (Open/In progress/Answered/Needs measurement): Open
    • Notes:

27. What observability minimum is required for incident triage (logs, traces, metrics)?

    • Status (Open/In progress/Answered/Needs measurement): Open
    • Notes:

F) Decision and Rollout Constraints

28. Which changes must be backward-compatible with current API contracts?

    • Status (Open/In progress/Answered/Needs measurement): Open
    • Notes:

29. What migration windows are acceptable for infrastructure-affecting changes?

    • Status (Open/In progress/Answered/Needs measurement): Open
    • Notes:

30. What evidence threshold is required before adopting a new transport or merge approach?

    • Status (Open/In progress/Answered/Needs measurement): Open
    • Notes:

31. Which design options are blocked without domain input from HPC operators or power users?

    • Status (Open/In progress/Answered/Needs measurement): Open
    • Notes:

Estimation Inputs Needed from Domain Experts

The following inputs are required to turn these open questions into concrete ADR comparisons:

1. HPC connection timing distributions for each target cluster (especially Ares).
2. Queue waiting-time distributions by queue/partition and time-of-day.
3. Typical and peak desired parallelism per simulation.
4. Typical and peak number of simultaneous simulations per user.
5. Result dump timings and file/page cardinality for representative scenarios.
6. Practical upper bounds considered acceptable by users for time-to-first-insight and time-to-completion.