# VEX Backfill Plan (DEVOPS-LNM-22-002)

## Goal
Run VEX observation/linkset backfill with monitoring, ensure events flow via NATS/Redis, and capture run artifacts.

## Steps
1) Pre-checks
   - Confirm DEVOPS-LNM-22-001 counts baseline (`.artifacts/lnm-counts.json`).
   - Ensure `STAGING_MONGO_URI`, `NATS_URL`, `REDIS_URL` available (read-only or test brokers).
2) Run VEX backfill
   - `dotnet run --project src/Concelier/StellaOps.Concelier.Backfill -- --mode=vex --batch-size=500 --max-conflicts=0 --mongo $STAGING_MONGO_URI --nats $NATS_URL --redis $REDIS_URL`
3) Metrics capture
   - Export per-run metrics to `.artifacts/vex-backfill-metrics.json` (duration, processed, conflicts, events emitted).
4) Event verification
   - Subscribe to `concelier.vex.backfill.completed` and `concelier.linksets.vex.upserted`; ensure queues drained.
5) Roll-forward checklist
   - Increase batch size to 2000 for prod; keep conflicts = 0; schedule maintenance window.

## Acceptance
- Zero conflicts; events observed; metrics file present; rollback plan documented.