Hi, In Hedwig talk (http://vimeo.com/13282102), it was mentioned that the primary use case for Hedwig comes from the distributed key-value store PNUTS in Yahoo!, but also said that the work is new.
Could you please about the following: Production readiness / Deployment 1. What is the production readiness of Hedwig / BookKeeper. Is it being used anywhere (like in PNUTS)? 2. Is Hedwig designed to use as a generic message bus or only for multi-datacenter operations? 3. Hedwig installation and deployment is done through a script hw.bash, but that is difficult to use especially in a production environment. Are there any other packages available that can simplify the deployment of hedwig. 4. How does BK/Hedwig handle zookeeper session expiry? Data Deletion, Handling data loss, Quorum 1. Does BookKeeper support deletion of old log entries which have been consumed. 2. How does Hedwig handles the case when all subscribers have consumed all the messages. In the talk, it was said that a subscriber can come back after hours, days or weeks. Is there any data retention / expiration policy for the data that is published? 3. How does Hedwig handles data loss? There is a replication factor, and a write operation must be accepted by majority of the bookies, but how data conflicts are handled? Is there any possibility of data conflict at all? Is the replication only for recovery? When the hub is reading data from bookies, does it reads from all the bookies to satisfy quorum read? Code What is the difference between PubSubServer, HedwigSubscriber, HedwigHubSubscriber. Is there any HelloWorld program that simply illustrates how to instantiate a hedwig client, and publish/consume messages. (HedwigBenchmark class is helpful, but was looking something like API documentation). -regards Amit
