Why should you care?

Multi-region API without synced vector index causes RAG to miss docs in secondary region — design must acknowledge lag.

See it live — copy this example

Paste into an ASP.NET Core 8+ / AgentNest project, then run with dotnet run (set your API keys in user-secrets).

// AgentNest.Distributed/VectorReplicationCoordinator.cs
public sealed class VectorReplicationCoordinator(IVectorStore primary, IVectorStore secondary, ILogger log)
{
    public async Task ReplicateChunkAsync(string tenantId, string id, float[] vector, string text, CancellationToken ct)
    {
        await primary.UpsertAsync(tenantId, id, vector, text, ct);
        try { await secondary.UpsertAsync(tenantId, id, vector, text, ct); }
        catch (Exception ex) { log.LogWarning(ex, "Secondary vector lag for {Id}", id); }
    }
}

What happened?

• Coordinator writes primary Qdrant synchronously, secondary best-effort with logged warning — explicit eventual consistency for DR region.
• Follow the steps below — typing the code yourself is the fastest way to learn.

Practice next

1. Document consistency model per store in architecture wiki.
2. Use correlation IDs across regional API calls.
3. Run chaos tests partitioning Redis cluster.
4. Add background reconciler comparing primary vs secondary vector counts.
5. Use Cosmos DB session consistency for global tenant config.

Remember

AgentNest distributed parts need explicit consistency choices. Replicate vectors with logged best-effort secondary writes. Design idempotent agents for message and retry duplicates.

Cross-region KB upload

Admin uploads CRM playbook; user in DR region queries immediately.

Outcome: Docs explain possible 60s lag; reconciler verifies secondary catch-up.