issue: update 4bc5 - add session progress, key findings, and next session plan

4bc5-relay-ngit-dev-migration-v2.md

@@ -36,11 +36,23 @@ relay.ngit.dev currently runs ngit-relay (reference implementation). We want to
 
 ### Migration Execution
 
-- [ ] Run analysis scripts on relay.ngit.dev
+- [x] Run analysis scripts on relay.ngit.dev
 - [ ] Review action-required repos, make decisions
 - [ ] Execute migration (switch domain, disable archive mode)
 - [ ] Validate migration success
 
+### Next Session Tasks
+
+- [ ] **Investigation:** Analyze why 315 repos didn't sync to archive
+- [ ] **Investigation:** Review 5 repos needing manual investigation
+- [ ] **Decision:** Choose migration approach (gradual vs full switch)
+- [ ] **Decision:** Determine when to merge branch to main
+- [ ] **Preparation:** Create migration checklist and rollback plan
+- [ ] **Execution:** Switch relay.ngit.dev domain to ngit-grasp
+- [ ] **Execution:** Disable archive mode
+- [ ] **Validation:** Run post-migration validation
+- [ ] **Cleanup:** Merge branch to main, close issue
+
 ## Progress
 
 ### 2026-01-23 [Session 16:00]
@@ -179,12 +191,249 @@ relay.ngit.dev currently runs ngit-relay (reference implementation). We want to
 - Easy rollback: remove `?ref=...` from flake input, rebuild (~5 min)
 - Timeline: ~2 hours for complete validation
 
-**Next Steps:**
-1. Push branch to remote
-2. Update nixos-config and deploy
-3. Run migration analysis
-4. Validate structured logging
-5. Merge to main after validation
+### 2026-01-23 [Session 14:00]
+- **Deployed branch to VPS** - Successfully updated nixos-config to use branch
+- **Ran full migration analysis** - All 5 phases completed successfully
+- **Resolved issues during deployment:**
+  - Git not available in systemd service environment (added to PATH)
+  - Script path discovery issues (fixed with proper directory detection)
+  - Phase 2 script missing (created `10-check-git-sync.sh`)
+- **Updated migration guide** with lessons learned and gotchas section
+
+**Analysis Results (relay.ngit.dev):**
+
+| Category | Count | Notes |
+|----------|-------|-------|
+| Complete in both | 231 | No action needed |
+| Complete in prod, MISSING from archive | 315 | **Needs investigation** |
+| Empty in both | 100 | Users never pushed |
+| In archive only | 4 | Deleted from prod? Or new? |
+| No match (refs differ) | 1 | Manual investigation |
+| Purgatory expiry events | 382 | Logged successfully |
+
+**Key Findings:**
+1. **315 repos missing from archive** - This is the main concern. Archive service is running but these repos didn't sync.
+2. **382 purgatory expiry events** - Structured logging working correctly
+3. **5 repos need manual investigation** - 4 in archive only, 1 with mismatched refs
+4. **100 empty repos** - Expected (users created but never pushed)
+
+**Current State:**
+- VPS running ngit-grasp from branch `4bc5-relay-ngit-dev-migration-v2`
+- Archive service syncing from relay.ngit.dev (prod ngit-relay)
+- All migration scripts working correctly
+- Structured logging producing expected output
+
+**Outstanding Questions:**
+1. Why didn't 315 repos sync to archive? Is this expected or a bug?
+2. What are the 4 repos in archive but not prod? (deleted? or new?)
+3. What's the 1 repo with mismatched refs?
+4. Should we do gradual cutover or full switch?
+5. When to merge branch to main?
+
+## Key Findings (Analysis Results)
+
+**Summary from 2026-01-23 analysis run:**
+
+| Metric | Value |
+|--------|-------|
+| Total repos in prod | 654 |
+| Total repos in archive | 268 |
+| Repos synced correctly | 231 |
+| Repos missing from archive | 315 |
+| Empty repos (never pushed) | 100 |
+| Repos needing manual review | 5 |
+| Purgatory expiry events | 382 |
+
+**Breakdown of 5 manual investigation repos:**
+- 4 repos exist in archive but NOT in prod (possible deletions or new repos)
+- 1 repo has mismatched refs between prod and archive
+
+**Interpretation:**
+- 231 repos (35%) synced correctly - archive mode working
+- 315 repos (48%) missing - need to understand why
+- 100 repos (15%) empty - expected, users never pushed
+- 5 repos (1%) need manual review - small number, manageable
+
+## Next Session Plan
+
+### Phase 1: Investigation (1-2 hours)
+
+**Goal:** Understand why 315 repos didn't sync and review the 5 manual investigation repos.
+
+**Tasks:**
+
+1. **Investigate 315 missing repos:**
+   - Check if archive service was running during their creation
+   - Look at timestamps: were these created before archive mode was enabled?
+   - Check if there's a pattern (specific users, time periods, repo sizes)
+   - Review archive service logs for errors
+   - Determine if this is expected behavior or a bug
+
+2. **Review 5 manual investigation repos:**
+   - **4 repos in archive only:** Check if they were deleted from prod, or if they're new repos created on archive
+   - **1 repo with mismatched refs:** Compare refs between prod and archive, determine which is correct
+
+3. **Validate archive mode is working:**
+   - Create a test repo on prod, verify it syncs to archive
+   - Check archive service health and connectivity
+
+**Decision Points:**
+- Is the 315 missing repos a bug that needs fixing before migration?
+- Or is it expected (repos created before archive mode)?
+- Do we need to manually sync these repos?
+
+### Phase 2: Decision Making (30 min)
+
+**Goal:** Make key decisions about migration approach.
+
+**Decisions to make:**
+
+1. **Migration approach:**
+   - **Option A: Full switch** - Change DNS, disable archive mode, done
+   - **Option B: Gradual cutover** - Run both in parallel, migrate users gradually
+   - **Recommendation:** Full switch is simpler if we're confident in the data
+
+2. **Handling 315 missing repos:**
+   - **Option A: Accept the gap** - These repos exist in prod, users can still access them
+   - **Option B: Manual sync** - Copy git data from prod to archive before switch
+   - **Option C: Re-announce** - Have users re-announce their repos after migration
+
+3. **Branch merge timing:**
+   - **Option A: Merge before migration** - Cleaner, but can't easily rollback
+   - **Option B: Merge after migration** - Can rollback to main if issues
+   - **Recommendation:** Merge after successful migration validation
+
+4. **Create migration checklist:**
+   - Pre-migration checks
+   - Migration steps
+   - Post-migration validation
+   - Rollback procedure
+
+### Phase 3: Pre-Migration Preparation (1-2 hours)
+
+**Goal:** Prepare everything needed for migration execution.
+
+**Tasks:**
+
+1. **Address investigation findings:**
+   - If 315 repos is a bug: fix it and re-run analysis
+   - If expected: document and proceed
+   - Handle the 5 manual investigation repos
+
+2. **Re-run analysis if needed:**
+   - If any fixes were made, re-run to verify
+   - Ensure numbers are stable
+
+3. **Prepare rollback plan:**
+   - Document exact steps to revert to ngit-relay
+   - Test rollback procedure (dry run)
+   - Ensure backups are in place
+
+4. **Create migration runbook:**
+   - Step-by-step commands
+   - Expected outputs at each step
+   - Verification checks
+   - Contact info for escalation
+
+5. **Notify stakeholders:**
+   - Announce maintenance window (if needed)
+   - Prepare status page update
+
+### Phase 4: Migration Execution (1-2 hours)
+
+**Goal:** Execute the migration and validate success.
+
+**Pre-Migration Checklist:**
+- [ ] All investigation items resolved
+- [ ] Rollback plan documented and tested
+- [ ] Backups verified
+- [ ] Stakeholders notified
+
+**Migration Steps:**
+
+1. **Switch domain to ngit-grasp:**
+   - Update DNS or reverse proxy configuration
+   - Point relay.ngit.dev to ngit-grasp service
+   - Verify connectivity
+
+2. **Disable archive mode:**
+   - Update ngit-grasp configuration
+   - Restart service
+   - Verify archive mode is disabled
+
+3. **Validate services:**
+   - Test WebSocket connection to relay.ngit.dev
+   - Test git clone/push operations
+   - Verify existing repos are accessible
+   - Check event propagation
+
+4. **Monitor for issues:**
+   - Watch logs for errors
+   - Monitor resource usage
+   - Check for user reports
+
+**Post-Migration Validation:**
+- [ ] WebSocket connections working
+- [ ] Git operations working
+- [ ] Existing repos accessible
+- [ ] New repos can be created
+- [ ] Events propagating correctly
+- [ ] No error spikes in logs
+
+### Phase 5: Post-Migration Cleanup (30 min)
+
+**Goal:** Finalize migration and clean up.
+
+**Tasks:**
+
+1. **Merge branch to main:**
+   - Create PR from `4bc5-relay-ngit-dev-migration-v2` to `main`
+   - Review changes
+   - Merge and delete branch
+
+2. **Update nixos-config:**
+   - Remove `?ref=...` from flake input
+   - Point back to main branch
+   - Rebuild to verify
+
+3. **Update documentation:**
+   - Mark migration guide as tested/validated
+   - Add any lessons learned
+   - Update architecture docs if needed
+
+4. **Archive analysis results:**
+   - Save analysis output for future reference
+   - Document final state
+
+5. **Close issue:**
+   - Update progress with final status
+   - Move to closed/ directory
+
+**Success Criteria:**
+- [ ] relay.ngit.dev running ngit-grasp
+- [ ] All existing repos accessible
+- [ ] New repos can be created
+- [ ] No degradation in service
+- [ ] Branch merged to main
+- [ ] Issue closed
+
+## Contingency Plans
+
+**If 315 missing repos is a critical bug:**
+- Pause migration
+- Fix the bug in ngit-grasp
+- Re-deploy and re-run analysis
+- Resume migration when fixed
+
+**If migration causes issues:**
+- Execute rollback plan (revert to ngit-relay)
+- Investigate root cause
+- Fix and retry
+
+**If archive data is corrupted:**
+- Restore from backup
+- Re-sync from prod
+- Retry migration
 
 ## Notes
 
@@ -192,3 +441,4 @@ relay.ngit.dev currently runs ngit-relay (reference implementation). We want to
 - **VPS:** Running NixOS
 - **Old worktree:** Can reference `/persistent/dcdev/clones/ngit-grasp/worktrees/820a-relay-ngit-dev-migration/` for existing scripts and learnings
 - **Target:** Simple, practical migration guide that works
+- **Branch deployed:** `4bc5-relay-ngit-dev-migration-v2` currently running on VPS