Your write will not succeed. You will get an exception like "xxxx could only be replicated to 0 nodes, instead of 1"
More details here: http://www.bigdataplanet.info/2013/10/Hadoop-Tutorial-Part-4-Write-Operations-in-HDFS.html http://cloudcelebrity.wordpress.com/2013/11/25/handling-hadoop-error-could-only-be-replicated-to-0-nodes-instead-of-1-during-copying-data-to-hdfs-or-with-mapreduce-jobs/ http://wiki.apache.org/hadoop/CouldOnlyBeReplicatedTo Regards, Shahab On Fri, Sep 19, 2014 at 8:16 AM, Raghavendra Chandra < raghavchandra.learn...@gmail.com> wrote: > Hi All, > > I have one very basic query regarding the replication factor in HDFS. > > Scenario: > > I have 4 node cluster : 3 data nodes and 1 master node. > > The replication factor is 3. So ideally each data node would get one > replica . > > Assume that meanwhile one of the data node went down. > > so ideally we will be having 2 data nodes. > > Queries: > > 1. How hadoop will take care of balancing of replicas as the required > replicas are 3 , but we have only 2 data nodes up and running. > > 2. What happens when we try to write new data into hdfs at this point of > time ? whether the write would be successful with only 2 data nodes and > replication factor 3 or it returns any error message? > > > These queries might be simple, but it would be really helpful if some one > can answer. > > Thanks and regards, > Raghav Chandra > >
