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.*
*Ans:* As here the replication factor is three. The data block will be replicated three time within 2 nodes. Block replication is random. *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?* *Ans:*It will write successfully. For further info please refer below link: http://hadoop.apache.org/docs/r1.2.1/hdfs_design.html Thanks, Adarsh D On Fri, Sep 19, 2014 at 5:46 PM, Raghavendra Chandra < [email protected]> 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 > >
