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From Kane Kane <kane.ist...@gmail.com>
Subject Re: Consumer offset is getting reset back to some old value automatically
Date Tue, 24 Jun 2014 19:36:50 GMT
Sorry, i meant 5 nodes in previous question.

On Tue, Jun 24, 2014 at 12:36 PM, Kane Kane <kane.isturm@gmail.com> wrote:
> Hello Neha,
>
>>>ZK cluster of 3 nodes will tolerate the loss of 1 node, but if there is a
> subsequent leader election for any reason, there is a chance that the
> cluster does not reach a quorum. It is less likely but still risky to some
> extent.
>
> Does it mean if you have to tolerate 1 node loss without any issues,
> you need *at least* 4 nodes?
>
> On Tue, Jun 24, 2014 at 11:16 AM, Neha Narkhede <neha.narkhede@gmail.com> wrote:
>> Can you elaborate your notion of "smooth"? I thought if you have
>> replication factor=3 in this case, you should be able to tolerate loss
>> of a node?
>>
>> Yes, you should be able to tolerate the loss of a node but if controlled
>> shutdown is not enabled, the delay between loss of the old leader and
>> election of the new leader will be longer.
>>
>> So, you mean ZK cluster of 3 nodes can't tolerate 1 node loss? I've
>> seen many recommendations to run 3-nodes cluster, does it mean in
>> cluster of 3 you won't be able to operate after loosing 1 node?
>>
>> ZK cluster of 3 nodes will tolerate the loss of 1 node, but if there is a
>> subsequent leader election for any reason, there is a chance that the
>> cluster does not reach a quorum. It is less likely but still risky to some
>> extent.
>>
>>
>> On Tue, Jun 24, 2014 at 2:44 AM, Hemath Kumar <hksrckmurthy@gmail.com>
>> wrote:
>>
>>> Yes kane i have the replication factor configured as 3
>>>
>>>
>>> On Tue, Jun 24, 2014 at 2:42 AM, Kane Kane <kane.isturm@gmail.com> wrote:
>>>
>>> > Hello Neha, can you explain your statements:
>>> > >>Bringing one node down in a cluster will go smoothly only if your
>>> > replication factor is 1 and you enabled controlled shutdown on the
>>> brokers.
>>> >
>>> > Can you elaborate your notion of "smooth"? I thought if you have
>>> > replication factor=3 in this case, you should be able to tolerate loss
>>> > of a node?
>>> >
>>> > >>Also, bringing down 1 node our of a 3 node zookeeper cluster is
risky,
>>> > since any subsequent leader election might not reach a quorum.
>>> >
>>> > So, you mean ZK cluster of 3 nodes can't tolerate 1 node loss? I've
>>> > seen many recommendations to run 3-nodes cluster, does it mean in
>>> > cluster of 3 you won't be able to operate after loosing 1 node?
>>> >
>>> > Thanks.
>>> >
>>> > On Mon, Jun 23, 2014 at 9:04 AM, Neha Narkhede <neha.narkhede@gmail.com>
>>> > wrote:
>>> > > Bringing one node down in a cluster will go smoothly only if your
>>> > > replication factor is 1 and you enabled controlled shutdown on the
>>> > brokers.
>>> > > Also, bringing down 1 node our of a 3 node zookeeper cluster is risky,
>>> > > since any subsequent leader election might not reach a quorum. Having
>>> > said
>>> > > that, a partition going offline shouldn't cause a consumer's offset
to
>>> > > reset to an old value. How did you find out what the consumer's offset
>>> > was?
>>> > > Do you have your consumer's logs around?
>>> > >
>>> > > Thanks,
>>> > > Neha
>>> > >
>>> > >
>>> > > On Mon, Jun 23, 2014 at 12:28 AM, Hemath Kumar <hksrckmurthy@gmail.com
>>> >
>>> > > wrote:
>>> > >
>>> > >> We have a 3 node cluster ( 3 kafka + 3 ZK nodes ) . Recently we
came
>>> > across
>>> > >> a strange issue where we wanted to bring one of the node down from
>>> > cluster
>>> > >> ( 1 kafka + 1 zookeeper) for doing a maintenance . But the movement
we
>>> > >> brought it to down on some of the topics ( only some partitions)
>>> > consumers
>>> > >> offset is reset some old value.
>>> > >>
>>> > >> Any reason why this is happened?. As of my knowledge when brought
one
>>> > node
>>> > >> down its should work smoothly with out any impact.
>>> > >>
>>> > >> Thanks,
>>> > >> Murthy Chelankuri
>>> > >>
>>> >
>>>

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