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https://issues.apache.org/jira/browse/HADOOP-5286?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Hemanth Yamijala updated HADOOP-5286:
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Component/s: (was: mapred)
dfs
Priority: Major (was: Blocker)
Fix Version/s: (was: 0.20.0)
Assignee: (was: Devaraj Das)
Hi Raghu, as has been suggested, we will change M/R to introduce multiple
threads for initialization. There was effort on this front in HADOOP-4664, that
we propose to take forward.
However, I feel we should spend a little more time and look at the datanode log
to make sure that it is indeed a hardware issue with the datanode in question
and then keep it aside. Since this has only occurred once, I don't think it
should be a blocker (I never did, in fact), and hence I've downgraded the
severity and removed the fix in version. We will be providing the logs to you
from the slow data node that we rebooted and it would be great if you can take
a quick look to determine there's no hidden problem.
> DFS client blocked for a long time reading blocks of a file on the JobTracker
> -----------------------------------------------------------------------------
>
> Key: HADOOP-5286
> URL: https://issues.apache.org/jira/browse/HADOOP-5286
> Project: Hadoop Core
> Issue Type: Bug
> Components: dfs
> Affects Versions: 0.20.0
> Reporter: Hemanth Yamijala
> Attachments: jt-log-for-blocked-reads.txt
>
>
> On a large cluster, we've observed that DFS client was blocked on reading a
> block of a file for almost 1 and half hours. The file was being read by the
> JobTracker of the cluster, and was a split file of a job. On the NameNode
> logs, we observed that the block had a message as follows:
> Inconsistent size for block blk_2044238107768440002_840946 reported from
> <ip>:<port> current size is 195072 reported size is 1318567
> Details follow.
>
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