How to configure the topic for posting messages back to a Kafka queue if writing to storage fails

[sjmittal]

I have not understood this part:
It includes a Storage Exception Handler plugin that will post messages back to a Kafka queue if writing to storage fails

The config specifies

KafkaRpcPlugin.groups = TsdbConsumer,TsdbRequeueConsumer
KafkaRpcPlugin.seh.topic.default = TSDB_Requeue

So does this mean that second group is created to post the failed messages back to the requeue topic?

Do I also need to specify this:
KafkaRpcPlugin.TsdbRequeueConsumer.topics = TSDB_Requeue

[manolama]

Failed writes (to HBase or whatnot) will post back to the "TSDB_Requeue" topic in Kafka. We want a separate topic so that the values don't circulate in the main data feed.

Instead we write to another topic, then create another consumer group (usually with fewer threads) that are dedicated to consuming just those requeued messages. So you do need KafkaRpcPlugin.TsdbRequeueConsumer.topics = TSDB_Requeue along with other KafkaRpcPlugin.TsdbRequeueConsumer..... settings.

[sjmittal]

Understood.
Also the writes of failed messages to re-queue topic would work only if at opentsdb level we set:
tsd.core.storage_exception_handler.enable=true (default is false)
and add
tsd.core.storage_exception_handler.plugin=net.opentsdb.tsd.KafkaStorageExceptionHandler

If these two are not set and even if we set the TsdbRequeueConsumer properties it will still not work. Correct?