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From Yury Ruchin <yuri.ruc...@gmail.com>
Subject Re: Zookeeper load burst during replication
Date Wed, 03 Dec 2014 11:22:05 GMT
Hi Guozhang,

No consumer clients were consuming when the broker was replicating, at
least none that would commit offsets to ZK. As for the controller log,
that's a good idea, I will try it out. Thanks!

2014-12-02 22:28 GMT+03:00 Guozhang Wang <wangguoz@gmail.com>:

> Kafka brokers uses ZK for metadata storage, and Kafka consumer clients uses
> ZK for offset and member management.
>
> For metadata storage, when there is replica state changes (for example like
> the new replica added after a broker restart in your case) the controller
> will try to write to ZK recording such changes, but this should just be one
> time and will not largely increase ZK load.
>
> So you can try to check:
>
> 1. If there are consumer clients running at the same time which would be
> writing to ZK heavily for committing offsets?
> 2. The controller log on the broker to see if it abnormally update such
> metadata to ZK during the period?
>
> Guozhang
>
> On Tue, Dec 2, 2014 at 7:38 AM, Yury Ruchin <yuri.ruchin@gmail.com> wrote:
>
> > Hello,
> >
> > In a multi-broker Kafka 0.8.1.1 setup, I had one broker crashed. I
> > restarted it after some noticeable time, so it started catching up the
> > leader very intensively. During the replication, I see that the disk load
> > on the ZK leader bursts abnormally, resulting in ZK performance
> > degradation. What could cause that? How does Kafka use ZK during
> > replication?
> >
> > Thanks,
> > Yury
> >
>
>
>
> --
> -- Guozhang
>

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