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Yang Yun edited comment on HDFS-15278 at 4/20/20, 9:35 AM: ----------------------------------------------------------- Thanks [~liuml07] for the review. Yes, our use case can be satisfied if enable the CreateFlag::IGNORE_CLIENT_LOCALITY, Thanks! The pain is that all user have to change their code with this flag. Currently, this feature is triggered only by setReplication to 1. With history chosen information, I think that it's more easy to implement the creating 1 replica file. Update to patch HDFS-15278.003.patch, define the sequentialBlocksDispersed as final. was (Author: hadoop_yangyun): Thanks [~liuml07] for the review. Yes, our use case can be satisfied if enable the CreateFlag::IGNORE_CLIENT_LOCALITY, Thanks! The pain is that all user have to change their code with this flag. Currently, this feature is triggered only by setReplication to 1. With history chosen information, I think the it's more easy to implement the creating 1 replica file. Update to patch HDFS-15278.003.patch, define the sequentialBlocksDispersed as final. > After execute ‘-setrep 1’, make sure that blocks of the file are dispersed > across different datanodes > ----------------------------------------------------------------------------------------------------- > > Key: HDFS-15278 > URL: https://issues.apache.org/jira/browse/HDFS-15278 > Project: Hadoop HDFS > Issue Type: Improvement > Components: namenode > Reporter: Yang Yun > Assignee: Yang Yun > Priority: Minor > Attachments: HDFS-15278.001.patch, HDFS-15278.002.patch, > HDFS-15278.003.patch > > > After execute ‘-setrep 1’, many of blocks of the file may locate on same > machine. Especially the file is written on one datanode machine. That causes > data hot spots and is hard to fix if this machine is down. > Add a chosen history to make sure that blocks of the file are dispersed > across different datanodes. -- This message was sent by Atlassian Jira (v8.3.4#803005) --------------------------------------------------------------------- To unsubscribe, e-mail: hdfs-issues-unsubscr...@hadoop.apache.org For additional commands, e-mail: hdfs-issues-h...@hadoop.apache.org