V6 startup takes ~5 hours repeatedly due to VDR history processing after restart (ACI + Azure File Share)

Summary

Our Nuts Node v6.1.5 startup regularly takes about 5 hours after deployment/restart.
The delay appears during VDR migration/history processing and repeated VC processing from the network.

Environment

• Nuts Node version: 6.1.5
• Deployment: Azure Container Instance (ACI)
• Storage:
  • SQL configured (storage.sql.connection is set)
  • BBolt data on mounted Azure File Share (/opt/nuts/data)
• TLS:
  • tls.certfile, tls.certkeyfile, tls.truststorefile configured and readable
• Network:
  • bootstrap node configured (nuts.test.kikstarter.nl:5555)
  • node connects/discovers peers successfully

Observed behavior

After deploy/restart, startup phase takes very long (~5 hours), especially around:

• Migrating VDR
• processing historical network/VDR data
• log pattern similar to Processing VC received from Nuts Network

We also see:

• Completed 0 migrations for SQL storage (so SQL schema migrations themselves are not the bottleneck)
• gRPC starts and peer discovery works

Expected behavior

• Startup should complete in reasonable time
• VDR history/migration should not repeatedly take hours on normal restarts
• Idempotent migration should be fast after first successful completion

Relevant startup logs

time="2026-04-15T10:24:05Z" level=debug msg="Running database migrations..." module=Storage
time="2026-04-15T10:24:05Z" level=info msg="Completed 0 migrations" module=Storage
...
time="2026-04-15T10:25:07Z" level=debug msg="Migrating VDR" module=core
time="2026-04-15T10:25:07Z" level=info msg="Running did:nuts migration: 'remove controller'" module=VDR
time="2026-04-15T10:25:07Z" level=info msg="Running did:nuts migration: 'document history'" module=VDR
time="2026-04-15T10:25:07Z" level=info msg="Running did:nuts migration: 'add did:web to subject'" module=VDR
...
time="2026-04-15T10:25:07Z" level=debug msg="Starting gRPC server on :5555" module=Network
time="2026-04-15T10:25:07Z" level=info msg="gRPC server started on :5555" module=Network
time="2026-04-15T10:25:07Z" level=debug msg="Discovered Nuts node" did="did:nuts:..." module=Network nodeAddr="grpc.****.test.***-v-da*******tion.nl:443"