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From sun liwei <slivey...@gmail.com>
Subject Re: Zookeeper in Kafka has gets a very low Performance
Date Thu, 13 Sep 2012 06:47:33 GMT
That's may be the root cause.

Here is something new I got:
Three zk servers are named: s1, s2, s3.
I restart zk on s3. After that the performance of this server gets better,
and I find that the number of connections / sessions on this server is
small(no more than 10). At the same time other two server(s1 and s2) both
have many (80+) connections / sessions and have a bad performance.
I guess most of the connections and sessions are doing the write
operations.

Even though there is a path ZOOKEEPER-1505, but it's not included in 3.3.*
branch. Will there be any work around for this issue?

Liwei


On Thu, Sep 13, 2012 at 1:07 PM, Alexander Shraer <shralex@gmail.com> wrote:

> Maybe it has something to do with the frequent writes delaying reads ?
> If a write is submitted to a follower and then a read (getData),
> no matter if the write and the read are to the same data, the read
> will block until the write completes. That's what ZOOKEEPER-1505 tries
> to address.
>
>
> Alex
>
>
> On Wed, Sep 12, 2012 at 6:44 PM, sun liwei <sliveysun@gmail.com> wrote:
> > Let me give more details:
> > I have two zookeeper clusters: A(3.3.4) and B(3.4.3).
> > A is used by Kafka only. B servers other application rather than Kafka.
> > The performance of A is very bad no matter which path I read with
> getData;
> > But B works well.
> >
> > My suspicion is that Kafka makes A slowing down. There are 1000+
> > consumers(each consumer is a node) in A. Kafka updates the value of all
> > these consumers very frequently. So, that means the write operations in A
> > is much more than read operations.
> >
> >
> > On Wed, Sep 12, 2012 at 6:33 PM, sun liwei <sliveysun@gmail.com> wrote:
> >
> >> The version of zookeeper is 3.3.4.
> >>
> >>
> >> On Wed, Sep 12, 2012 at 6:07 PM, sun liwei <sliveysun@gmail.com> wrote:
> >>
> >>> Here is what I haveļ¼š
> >>>
> >>>
> >>>    - zookeeper cluster with 3 severs
> >>>    - 1700+ kafka topics (that means there are 1700+ children under path
> >>>    '/brokers/topics'), these topics are written frequently by kafka.
> >>>    - log file size is 67108880 byte,  snapshot file size is 4192072
> >>>    byte, new log/snapshot files are created every one or two minutes
> >>>
> >>> The problem is that it takes more than 40ms to getData of a single
> topic.
> >>> I have another zookeeper cluster and the getData takes no more than
> 2ms to
> >>> getData of a single path. This cluster doesn't server kafka.
> >>>
> >>> Any body knows why the performance is so bad?
> >>>
> >>> Many thanks and best regards.
> >>>
> >>> Liwei
> >>>
> >>
> >>
>

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