Hi Balasubramanian
Why the (topics/partition) combination which has broker with id 0 in their
replication list does not find a new broker and replicate the messages? Is
this the intended behavior of Kafka ?
Do you mean, why does Broker 0 stay in the replication set for partitions when
it goes down?
This seems like a design decision as it means if 0 has a transient failure, due
to a network blip or a restart, it will rejoin it's partitions when it comes
back up. This would result in the least network activity as it would have most
of the log already on disk and would just need to catch up.
One could also imagine a scenario where a broker went down because of load.
This broker's partition assignments would get reassigned to other highly loaded
brokers which could cause a cascading failure (I think).
You can reassign partitions with
https://cwiki.apache.org/confluence/display/KAFKA/Replication+tools#Replicationtools-6.ReassignPartitionsTool.
It is also a very good idea to monitor the JMX bean for under replicated
partitions as this would indicate the partitions at risk.
---
Daniel
On 30/06/2014, at 3:26 pm, Balasubramanian Jayaraman
balasubramanian.jayara...@autodesk.com wrote:
Hi,
I have created a topic with the number of partitions as 5 and replication
factor as 3. I have 5 Kafka brokers up and running.
What happens if a broker with broker id '0' is down ?
My observation is as follows.
1. The brokers are running as before and responding to the producers as
well as the consumers.
2. A new leader is elected for all the topics/partitions for which the
broker with id 0 is the leader.
3. The ISR is updated with the available brokers (in this case 2
brokers for some topic/partition combination).
4. The ISR has 3 brokers after the broker with id 0 is up and running
again.
I have a question on this:
