Hi All, We have seen data loss in Kafka, once we restarted the cluster.
We have 3 Brokers in a cluster. In order to prevent data loss we have configured *min.insync.replicas=2* for all topics. Initially, when all brokers(1,2,3) are live we produced few messages(say 50 messages). Now we killed broker 1 and started producing the messages, after 20 messages were produced, we killed broker 2. Since number of brokers in ISR are less than 2, producer requests failed(as expected). After this, We killed broker 3, so at this point all brokers are down. Now, we started broker 1, which has 50 messages. Broker 1 became leader of all partition it owned. Since brokers in ISR are less than 2, producer request failed. After this, We started broker 2, the logs got truncated at broker 2 and set offset to 50. *Here we have lost those 20 messages.* But, in this case broker 1 should release the leadership and becomes follower in-order to get those 20 messages so that no data would be lost. Is there any suggestion to prevent data loss in this case? Note: We have tested the same case in 0.8.2.1 and 0.10 release. Thanks and Regards, Madhukar
