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Date: Sat, 8 Sep 2012 02:16:08 +1100 (NCT)
From: "Ivan Mitic (JIRA)" <jira@apache.org>
To: common-issues@hadoop.apache.org
Message-ID: <1011087102.50589.1347030968158.JavaMail.jiratomcat@arcas>
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Subject: [jira] [Commented] (HADOOP-8694) Create true symbolic links on
 Windows
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    [ https://issues.apache.org/jira/browse/HADOOP-8694?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13450700#comment-13450700 ] 

Ivan Mitic commented on HADOOP-8694:
------------------------------------

Thanks Chuan for the patch. It's great to see symlink functionality on Windows.

A few minor comments:
1. FileUtil#symlink: Should we log a warning on {{ExitCodeException}} to be consistent with the previous behavior?
2. symlink.c: IMO, we should remove {{CreateJunctionPointW}} if it is not used in the codebase.
3. Would be good to add a few test cases for the symlink functionality.
                
> Create true symbolic links on Windows
> -------------------------------------
>
>                 Key: HADOOP-8694
>                 URL: https://issues.apache.org/jira/browse/HADOOP-8694
>             Project: Hadoop Common
>          Issue Type: Bug
>    Affects Versions: 1-win
>            Reporter: Chuan Liu
>            Assignee: Chuan Liu
>             Fix For: 1-win
>
>         Attachments: HADOOP-8694-branch-1-win.patch, secpol.png
>
>
> In branch-1-win, we currently copy files for symbolic links in Hadoop on Windows. We have talked to [~davidlao] who made the original fix, and did some investigation on Windows. Windows began to support symbolic links (symlinks) since Vista/Server 2008. The original reason to copy files instead of creating actual symlinks is that only Administrators has the privilege to create symlinks on Windows _by default_. After talking to NTFS folks, we knew the reason for that is mostly due to security, and this default behavior may not be changed in near future. Though this behavior can be changed via  the Local Security Policy management console, i.e. secpol.msc, under Security Settings\Local Policies\User Rights Assignment\Create symbolic links.
>  
> In Hadoop, symlinks is mostly used to for DistributedCache and attempted logs. We felt the usages are important enough for us to provide true symlinks support, and users need to have the symlink creation privilege enabled on Windows to use Hadoop.
> This JIRA is created to tracking symlink support on Windows.

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