Multi-Region Data Replication with Amazon DynamoDB Global Tables
Part 4 of the multi-region serverless series: giving every region its own low-latency copy of the data with DynamoDB Global Tables. How to set replication up, how region-aware reads and writes work, and what last-writer-wins conflict resolution actually means for you.
The final part of the "Going Global with Serverless" series. Lambda is multi-region, the API is multi-region, and now the data has to be too, or every write still crosses an ocean. DynamoDB Global Tables give each region a full replica that DynamoDB keeps in sync for you. This piece covers the setup and, more importantly, the behavior you're signing up for.
Setup is short: create the table in a primary region, enable global table replication, pick the additional regions (the CLI examples use us-east-1 and eu-west-1). After that, your app does region-aware reads and writes, hitting the local replica, with Python and Boto3 examples for put and get. Replication is asynchronous, so the model is eventually consistent across regions. Conflicts are resolved by last-writer-wins by default, and the article's advice is to lean on that consciously: carry your own timestamps, and for anything where LWW isn't good enough, use Lambda plus DynamoDB Streams to handle reconciliation yourself. The example is an e-commerce user-profile store sitting behind API Gateway, Route 53, and CloudFront.
Key takeaways
- Global Tables trade consistency for latency on purpose: local reads/writes are fast, cross-region writes lag; design features that tolerate it
- Last-writer-wins means silent data loss: two near-simultaneous writes in different regions, one wins by timestamp; carry your own timestamps, use Streams plus Lambda for real reconciliation
- Keep reads and writes region-aware: hardcode one region's endpoint and you've rebuilt the latency
Who this is for
Developers building serverless multi-region apps who need the data layer to match. Assumes you know single-region DynamoDB (tables, keys, Boto3 or another SDK). This is part 4, so parts 1 through 3 cover the compute, API, and routing it sits on top of. It doesn't get into capacity and billing, Streams internals, or version differences.
The full walkthrough, with the CLI setup and the Boto3 read/write examples, is on DEV.to.