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From "Amar Kamat (JIRA)" <j...@apache.org>
Subject [jira] Updated: (HADOOP-2175) Blacklisted hosts may not be able to serve map outputs
Date Fri, 14 Mar 2008 16:56:25 GMT

     [ https://issues.apache.org/jira/browse/HADOOP-2175?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel

Amar Kamat updated HADOOP-2175:

    Attachment: HADOOP-2175-v1.patch

Attaching a patch that marks blacklisted trackers as lost. Since {{FAILED}} and {{KILLED}}
tasks have associated counts, this patch ignores these tasks. {{RUNNING}} and {{SUCCEEDED}}
tasks are re-scheduled. If a task is {{FAILED}} its still considered {{FAILED}} because 
1) There are counts associated with it and is used for killing a {{TIP}}
2) Changing the state causes inconsistency between the failed-task counts and actual number
of failed-tasks.

> Blacklisted hosts may not be able to serve map outputs
> ------------------------------------------------------
>                 Key: HADOOP-2175
>                 URL: https://issues.apache.org/jira/browse/HADOOP-2175
>             Project: Hadoop Core
>          Issue Type: Bug
>          Components: mapred
>            Reporter: Runping Qi
>            Assignee: Amar Kamat
>         Attachments: HADOOP-2175-v1.patch
> After a node fails 4 mappers (tasks), it is added to blacklist thus it will no longer
accept tasks.
> But, it will continue serve the map outputs of any mappers that ran successfully there.

> However, the node may not be able serve the map outputs either. 
> This will cause the reducers to mark the corresponding map outputs as from slow hosts,

> but continue to try to get the map outputs from that node.
> This may lead to waiting forever.

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