[ https://issues.apache.org/jira/browse/HDFS-12827?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16256077#comment-16256077 ]
Bharat Viswanadham commented on HDFS-12827: ------------------------------------------- Hi [~surinuthalap...@live.com] In the latest design document, it is mentioned correctly {code:java} when the replication factor is three, HDFS’s placement policy is to put one replica on the local machine if the writer is on a datanode, otherwise on a random datanode, another replica on a node in a different (remote) rack, and the last on a different node in the same remote rack {code} . Pls let me know any more is needed? > Need Clarity on Replica Placement: The First Baby Steps in HDFS Architecture > documentation > ------------------------------------------------------------------------------------------ > > Key: HDFS-12827 > URL: https://issues.apache.org/jira/browse/HDFS-12827 > Project: Hadoop HDFS > Issue Type: Improvement > Components: documentation > Reporter: Suri babu Nuthalapati > Priority: Minor > > The placement should be this: > https://hadoop.apache.org/docs/r1.2.1/hdfs_design.html > HDFS’s placement policy is to put one replica on one node in the local rack, > another on a node in a different (remote) rack, and the last on a different > node in the same remote rack. > Hadoop Definitive guide says the same and I have tested and saw the same > behavior as above. > ############ > But the documentation in the versions after r2.5.2 it was mentioned as: > http://hadoop.apache.org/docs/r2.5.2/hadoop-project-dist/hadoop-hdfs/HdfsDesign.html > HDFS’s placement policy is to put one replica on one node in the local rack, > another on a different node in the local rack, and the last on a different > node in a different rack. -- This message was sent by Atlassian JIRA (v6.4.14#64029) --------------------------------------------------------------------- To unsubscribe, e-mail: hdfs-issues-unsubscr...@hadoop.apache.org For additional commands, e-mail: hdfs-issues-h...@hadoop.apache.org