title: Kafka MirrorMaker's consumer not fetching all messages from topics
body: <p>I am trying to setup a Kafka Mirror mechanism, but it seems the Kafka MirrorMaker's consumer from the source Kafka cluster only reads from new incoming data to the topics as soon as the mirror maker process is started, i.e. it does not read historically saved data in the topics previously.</p>
  
  <p>I am using Kafka MirrorMaker class for that as: </p>
  
  <p><code>/bin/kafka-run-class.sh kafka.tools.MirrorMaker --consumer.config consumer.config --num.streams 2 --producer.config producer.config --whitelist=".*"</code></p>
  
  <p><code>consumer.config</code> to read from Kafka source cluster, as:</p>
  
  <p><code>zookeeper.connect=127.0.0.1:2181</code></p>
  
  <p><code>zookeeper.connection.timeout.ms=6000</code></p>
  
  <p><code>group.id=kafka-mirror</code></p>
  
  <p>and <code>producer.config</code> settings to produce to the new Kafka mirrored cluster:</p>
  
  <p><code>metadata.broker.list=localhost:9093</code></p>
  
  <p><code>producer.type=sync</code></p>
  
  <p><code>compression.codec=none</code></p>
  
  <p><code>serializer.class=kafka.serializer.DefaultEncoder</code></p>
  
  <p>Is there a way to define the consumer of Kafka MirrorMaker to read from the beginning of the topics of my source Kafka cluster? A bit strange, because I have defined in the <code>consumer.config</code> settings a new consumer group (<code>kafka-mirror</code>), so the consumer should just read from <code>offset 0</code>, i.e. from beginning of topics.</p>
  
  <p>Many thanks in advance!</p>