Is there a fundamental reason for not allowing creation of new topics while in an under-replicated state? For systems that use automatic topic creation, it seems like losing a node in this case is akin to the cluster being unavailable, if one of the nodes goes down, etc.
On Tue, Oct 15, 2013 at 1:25 PM, Joel Koshy <jjkosh...@gmail.com> wrote: > Steve - that's right. I think Monika wanted clarification on what > would happen if replication factor is two and only one broker is > available. In that case, you won't be able to create new topics with > replication factor two (you should see an AdministrationException > saying the replication factor is larger than available brokers). > > However, you can send messages to available partitions of topics that > have already been created - because the ISR would shrink to only one > replica for those topics - although the cluster would be in an > under-replicated state. This is covered in the documentation > (http://kafka.apache.org/documentation.html#replication) under the > discussion about ISR. > > Thanks, > > Joel > > On Tue, Oct 15, 2013 at 10:19 AM, Steve Morin <st...@stevemorin.com> > wrote: > > If you have a double broker failure with replication factor of 2 and only > > have 2 brokers in the cluster. Wouldn't every partition be not > available? > > > > > > On Tue, Oct 15, 2013 at 8:48 AM, Jun Rao <jun...@gmail.com> wrote: > > > >> If you have double broker failures with a replication factor of 2, some > >> partitions will not be available. When one of the brokers comes back, > the > >> partition is made available again (there is potential data loss), but > in an > >> under replicated mode. After the second broker comes back, it will > catch up > >> from the other replica and the partition will eventually be fully > >> replicated. There is no need to change the replication factor during > this > >> process. > >> > >> As for ZK, you can always use the full connection string. ZK will pick > live > >> servers to establish connections. > >> > >> Thanks, > >> > >> Jun > >> > >> > >> On Tue, Oct 15, 2013 at 3:46 AM, Monika Garg <gargmon...@gmail.com> > wrote: > >> > >> > I have 2 nodes kafka cluster with default.replication.factor=2,is set > in > >> > server.properties file. > >> > > >> > I removed one node-in removing that node,I killed Kafka > process,removed > >> all > >> > the kafka-logs and bundle from that node. > >> > > >> > Then I stopped my remaining running node in the cluster and started > >> > again(default.replication.factor is still set to 2 in this node > >> > server.properties file). > >> > I was expecting some error/exception as now I don't have two nodes in > my > >> > cluster.But I didn't get any error/exception and my node successfully > >> > started and I am able to create topics on it. > >> > > >> > So should the "default.replication.factor" be updated from > >> > "default.replication.factor=2" to "default.replication.factor=1" , in > the > >> > remaining running node? > >> > > >> > Similarly if there are two external zookeeper > >> > nodes(zookeeper.connect=host1:port1,host2:port1) in my cluster and > now I > >> > have removed one zookeeper node(host1:port1) from the cluster,So > should > >> the > >> > property "zookeeper.connect" be updated from > >> > (zookeeper.connect=host1:port1,host2:port1) to > >> > (zookeeper.connect=host2:port1)? > >> > > >> > -- > >> > *Moniii* > >> > > >> >
