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https://issues.apache.org/jira/browse/KAFKA-2143?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14648444#comment-14648444
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Rafael Bagmanov commented on KAFKA-2143:
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I would like to add that we are experiencing this issue quite often.
And the situation get worse when we have configs like this
replication factor: 2
unclean.leader.election.enable: true
This leads to loss of a whole partition in case of two network glitches
happening in a row.
The failure scenario looks like this:
we have replica.lag.max.messages: 4000 so I'm guessing follower is always
little bit behind leader for high volume topic (which means leader has a larger
offset value than the follower)
1) Broker A (leader) has committed offset up-to 5000
2) Broker B (follower) has committed offset up to 3000 (he is still in ISR
because of replica.lag.max.messages)
***network glitch happens***
3) Broker B becomes a leader, Broker A becomes a follower
4) Broker A (follower) asks leader for messages starting from 5000
5) Broker A (follower) receives message that this is invalid offset (Broker B
has only 3000) and drops partition to 0
***network glitch happens***
6) Broker A becomes a leader (unclean election), Broker B becomes a follower
7) Broker B (follower) ask leader for messages starting from 3000
8) Broker B (follower) receives message that this is invalid offset (Broker A
has only 0) and drops partition to 0
As a result we lost partition because of 2 network glitches.
And if the configs are
replication factor: 2
unclean.leader.election.enable: false (!)
the scenario repeats up to 5th step, but then Broker A got kicked out of ISR
and unclean election is not happening.
> Replicas get ahead of leader and fail
> -------------------------------------
>
> Key: KAFKA-2143
> URL: https://issues.apache.org/jira/browse/KAFKA-2143
> Project: Kafka
> Issue Type: Bug
> Components: replication
> Affects Versions: 0.8.2.1
> Reporter: Evan Huus
>
> On a cluster of 6 nodes, we recently saw a case where a single
> under-replicated partition suddenly appeared, replication lag spiked, and
> network IO spiked. The cluster appeared to recover eventually on its own,
> Looking at the logs, the thing which failed was partition 7 of the topic
> {{background_queue}}. It had an ISR of 1,4,3 and its leader at the time was
> 3. Here are the interesting log lines:
> On node 3 (the leader):
> {noformat}
> [2015-04-23 16:50:05,879] ERROR [Replica Manager on Broker 3]: Error when
> processing fetch request for partition [background_queue,7] offset 3722949957
> from follower with correlation id 148185816. Possible cause: Request for
> offset 3722949957 but we only have log segments in the range 3648049863 to
> 3722949955. (kafka.server.ReplicaManager)
> [2015-04-23 16:50:05,879] ERROR [Replica Manager on Broker 3]: Error when
> processing fetch request for partition [background_queue,7] offset 3722949957
> from follower with correlation id 156007054. Possible cause: Request for
> offset 3722949957 but we only have log segments in the range 3648049863 to
> 3722949955. (kafka.server.ReplicaManager)
> [2015-04-23 16:50:13,960] INFO Partition [background_queue,7] on broker 3:
> Shrinking ISR for partition [background_queue,7] from 1,4,3 to 3
> (kafka.cluster.Partition)
> {noformat}
> Note that both replicas suddenly asked for an offset *ahead* of the available
> offsets.
> And on nodes 1 and 4 (the replicas) many occurrences of the following:
> {noformat}
> [2015-04-23 16:50:05,935] INFO Scheduling log segment 3648049863 for log
> background_queue-7 for deletion. (kafka.log.Log) (edited)
> {noformat}
> Based on my reading, this looks like the replicas somehow got *ahead* of the
> leader, asked for an invalid offset, got confused, and re-replicated the
> entire topic from scratch to recover (this matches our network graphs, which
> show 3 sending a bunch of data to 1 and 4).
> Taking a stab in the dark at the cause, there appears to be a race condition
> where replicas can receive a new offset before the leader has committed it
> and is ready to replicate?
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