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https://issues.apache.org/jira/browse/YARN-6289?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15906088#comment-15906088
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Huangkaixuan commented on YARN-6289:
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Thanks [~leftnoteasy]
For #1 - Can you explain a little more, the answer is not clear, it should say
more conclusively that - MR is using FileSystem.getFileBlockLocations but Yarn
is not honoring locality in default scheduling mode.
For #2 - Since the data is all rack local, we are not expecting this experiment
to help. Is there a reason you think it might?
For #3 - There were no other jobs running on the cluster at the same time and
we thought we should get 100% locality all the time. Can you please explain how
to get the data locality here?
> Fail to achieve data locality when runing MapReduce and Spark on HDFS
> ---------------------------------------------------------------------
>
> Key: YARN-6289
> URL: https://issues.apache.org/jira/browse/YARN-6289
> Project: Hadoop YARN
> Issue Type: Bug
> Components: distributed-scheduling
> Environment: Hardware configuration
> CPU: 2 x Intel(R) Xeon(R) E5-2620 v2 @ 2.10GHz /15M Cache 6-Core 12-Thread
> Memory: 128GB Memory (16x8GB) 1600MHz
> Disk: 600GBx2 3.5-inch with RAID-1
> Network bandwidth: 968Mb/s
> Software configuration
> Spark-1.6.2 Hadoop-2.7.1
> Reporter: Huangkaixuan
> Attachments: Hadoop_Spark_Conf.zip, YARN-DataLocality.docx
>
>
> When running a simple wordcount experiment on YARN, I noticed that the task
> failed to achieve data locality, even though there is no other job running on
> the cluster at the same time. The experiment was done in a 7-node (1 master,
> 6 data nodes/node managers) cluster and the input of the wordcount job (both
> Spark and MapReduce) is a single-block file in HDFS which is two-way
> replicated (replication factor = 2). I ran wordcount on YARN for 10 times.
> The results show that only 30% of tasks can achieve data locality, which
> seems like the result of a random placement of tasks. The experiment details
> are in the attachment, and feel free to reproduce the experiments.
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