Did you have a gc pause around that time on the server ? What are your server's current gc settings ?
Thanks, Neha On Mon, Mar 25, 2013 at 8:48 PM, Yonghui Zhao <zhaoyong...@gmail.com> wrote: > Thanks Neha, btw have you seen this exception. We didn't restart any > service it happens in deep night. > > java.lang.RuntimeException: A broker is already registered on the path > /brokers/ids/0. This probably indicates that you either have configured a > brokerid that is already in use, or else you have shutdown this broker and > restarted it faster than the zookeeper timeout so it appears to be > re-registering. > at > kafka.server.KafkaZooKeeper.registerBrokerInZk(KafkaZooKeeper.scala:57) > at > kafka.server.KafkaZooKeeper$SessionExpireListener.handleNewSession(KafkaZooKeeper.scala:100) > at org.I0Itec.zkclient.ZkClient$4.run(ZkClient.java:472) > at org.I0Itec.zkclient.ZkEventThread.run(ZkEventThread.java:71) > [2013-03-26 02:07:19,155] INFO re-registering broker info in ZK for broker > 0 (kafka.server.KafkaZooKeeper) > [2013-03-26 02:07:19,155] INFO Registering broker /brokers/ids/0 > (kafka.server.KafkaZooKeeper) > [2013-03-26 02:07:19,611] INFO conflict in /brokers/ids/0 data: > 127.0.0.1-1364234839275:127.0.0.1:9093 stored data: 127.0.0.1-1364227372971: > 127.0.0.1:9093 (kafka.utils.ZkUtils$) > [2013-03-26 02:07:19,611] ERROR Error handling event ZkEvent[New session > event sent to kafka.server.KafkaZooKeeper$SessionExpireListener@40f8c9bf] > (org.I0Itec.zkclient.ZkEventThread) > java.lang.RuntimeException: A broker is already registered on the path > /brokers/ids/0. This probably indicates that you either have configured a > brokerid that is already in use, or else you have shutdown this broker and > restarted it faster than the zookeeper timeout so it appears to be > re-registering. > at > kafka.server.KafkaZooKeeper.registerBrokerInZk(KafkaZooKeeper.scala:57) > at > kafka.server.KafkaZooKeeper$SessionExpireListener.handleNewSession(KafkaZooKeeper.scala:100) > at org.I0Itec.zkclient.ZkClient$4.run(ZkClient.java:472) > at org.I0Itec.zkclient.ZkEventThread.run(ZkEventThread.java:71) > > > > 2013/3/26 Neha Narkhede <neha.narkh...@gmail.com> > >> That really depends on your consumer application's memory allocation >> patterns. If it is a thin wrapper over a Kafka consumer, I would imagine >> you can get away with using CMS for the tenured generation and parallel >> collector for the new generation with a small heap like 1gb or so. >> >> Thanks, >> Neha >> >> On Monday, March 25, 2013, Yonghui Zhao wrote: >> >> > Any suggestion on consumer side? >> > 在 2013-3-25 下午9:49，"Neha Narkhede" <neha.narkh...@gmail.com<javascript:;> >> > >写道： >> > >> > > For Kafka 0.7 in production at Linkedin, we use a heap of size 3G, new >> > gen >> > > 256 MB, CMS collector with occupancy of 70%. >> > > >> > > Thanks, >> > > Neha >> > > >> > > On Sunday, March 24, 2013, Yonghui Zhao wrote: >> > > >> > > > Hi Jun, >> > > > >> > > > I used kafka-server-start.sh to start kafka, there is only one jvm >> > > setting >> > > > "-Xmx512M“ >> > > > >> > > > Do you have some recommend GC setting? Usually our sever has 32GB >> or >> > > 64GB >> > > > RAM. >> > > > >> > > > 2013/3/22 Jun Rao <jun...@gmail.com> >> > > > >> > > > > A typical reason for many rebalancing is the consumer side GC. If >> so, >> > > you >> > > > > will see logs in the consume saying sth like "expired session" for >> > ZK. >> > > > > Occasional rebalances are fine. Too many rebalances can slow down >> the >> > > > > consumption and you will need to tune your GC setting. >> > > > > >> > > > > Thanks, >> > > > > >> > > > > Jun >> > > > > >> > > > > On Thu, Mar 21, 2013 at 11:07 PM, Yonghui Zhao < >> > zhaoyong...@gmail.com >> > > > > >wrote: >> > > > > >> > > > > > Yes, before consumer exception: >> > > > > > >> > > > > > 2013/03/21 12:07:17.909 INFO [ZookeeperConsumerConnector] [] >> > > > > > 0_lg-mc-db01.bj-1363784482043-f98c7868 *end rebalancing >> > > > > > consumer*0_lg-mc-db01.bj-1363784482043-f98c7868 try #0 >> > > > > > 2013/03/21 12:07:17.911 INFO [ZookeeperConsumerConnector] [] >> > > > > > 0_lg-mc-db01.bj-1363784482043-f98c7868 *begin rebalancing >> > > > > > consumer*0_lg-mc-db01.bj-1363784482043-f98c7868 try #0 >> > > > > > 2013/03/21 12:07:17.934 INFO [FetcherRunnable] [] FetchRunnable-0 >> > > start >> > > > > > fetching topic: sms part: 0 offset: 43667888259 from >> > 127.0.0.1:9093 >> > > > > > 2013/03/21 12:07:17.940 INFO [SimpleConsumer] [] Reconnect in >> > > > multifetch >> > > > > > due to socket error: >> > > > > > java.nio.channels.*ClosedByInterruptException* >> > > > > > at java.nio.channels.spi.*AbstractInterruptibleChannel* >> > > > > > .end(AbstractInterruptibleChannel.java:201) >> > > > > > >> > > > > > >> > > > > > 2013/03/21 12:07:17.978 INFO [ZookeeperConsumerConnector] [] >> > > > > > 0_lg-mc-db01.bj-1363784482043-f98c7868 *end rebalancing >> > > > > > consumer*0_lg-mc-db01.bj-1363784482043-f98c7868 try #0 >> > > > > > 2013/03/21 12:07:18.004 INFO [FetcherRunnable] [] FetchRunnable-0 >> > > start >> > > > > > fetching topic: sms part: 0 offset: 43667888259 from >> > 127.0.0.1:9093 >> > > > > > 2013/03/21 12:07:18.066 INFO [ZookeeperConsumerConnector] [] >> > > > > > 0_lg-mc-db01.bj-1363784482043-f98c7868 *begin rebalancing >> consume*r >> > > > > > 0_lg-mc-db01.bj-1363784482043-f98c7868 try #0 >> > > > > > 2013/03/21 12:07:18.176 INFO [SimpleConsumer] [] Reconnect in >> > > > multifetch >> > > > > > due to socket error: >> > > > > > java.nio.channels.*ClosedByInterruptException* >> > > > > > at java.nio.channels.spi.*AbstractInterruptibleChannel* >> > > > > > .end(AbstractInterruptibleChannel.java:201) >> > > > > > >> > > > > > >> > > > > > So you think it is normal? How can we avoid this exception? >> > > > > > >> > > > > > I used 4 partitions in kafka, use only 1 partition？ >> > > > > > >> > > > > > >> > > > > > >> > > > > > 2013/3/22 Jun Rao <jun...@gmail.com> >> > > > > > >> > > > > > > Do you see any rebalances in the consumer? Each rebalance will >> > > > > interrupt >> > > > > > > existing fetcher threads first. >> > > > > > > >> > > > > > > Thanks, >> > > > > > > >> > > > > > > Jun >> > > > > > > >> > > > > > > On Thu, Mar 21, 2013 at 9:40 PM, Yonghui Zhao < >> > > zhaoyong...@gmail.com >> > >>
