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Date: Mon, 12 Nov 2012 22:57:14 +0000 (UTC)
From: "Daryn Sharp (JIRA)" <jira@apache.org>
To: hdfs-issues@hadoop.apache.org
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Subject: [jira] [Commented] (HDFS-4178) shell scripts should not close
 stderr
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    [ https://issues.apache.org/jira/browse/HDFS-4178?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13495727#comment-13495727 ] 

Daryn Sharp commented on HDFS-4178:
-----------------------------------

+1 Although it's worth noting that I don't think data corruption will occur, just a EBADF (Bad file descriptor) error if anything attempts to write to stderr.  I'll let there be a second opinion on this one.
                
> shell scripts should not close stderr
> -------------------------------------
>
>                 Key: HDFS-4178
>                 URL: https://issues.apache.org/jira/browse/HDFS-4178
>             Project: Hadoop HDFS
>          Issue Type: Bug
>          Components: scripts
>    Affects Versions: 2.0.2-alpha
>            Reporter: Andy Isaacson
>            Assignee: Andy Isaacson
>         Attachments: hdfs4178.txt
>
>
> The {{start-dfs.sh}} and {{stop-dfs.sh}} scripts close stderr for some subprocesses using the construct
> bq. {{2>&-}}
> This is dangerous because child processes started up under this scenario will re-use filedescriptor 2 for opened files.  Since libc and many other codepaths assume that filedescriptor 2 can be written to in error conditions, this can potentially result in data corruption.
> Much better to redirect stderr using the construct {{2>/dev/null}}.

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