The story of going form S3 to CouchDB and Redis and then back to S3 and Redis for ad serving:
The solution to this situation has a touch of irony. With Redis in place, we replaced CouchDB for placement- and ad-data with S3. Since we weren’t using any CouchDB-specific features, we simply published all the documents to S3 buckets instead. We still did the Redis cache warming upfront and data updates in the background. So by decoupling the application from the persistence layer using Redis, we also removed the need for a super fast database backend. We didn’t care that S3 is slower than a local CouchDB, since we updated everything asynchronously.
Besides the detailed blog post there’s also a slidedeck:
Original title and link: From S3 to CouchDB and Redis and Then Half Way Back for Serving Ads ( ©myNoSQL)