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 <[email protected]> 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 <[email protected]> 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 <[email protected]> wrote: > > > >> The version of zookeeper is 3.3.4. > >> > >> > >> On Wed, Sep 12, 2012 at 6:07 PM, sun liwei <[email protected]> wrote: > >> > >>> Here is what I haveļ¼ > >>> > >>> > >>> - 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 > >>> > >> > >> >
