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HDFS, mail # user - Re: [jira] Commented: (HADOOP-4539) Streaming Edits to a Backup Node.


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Re: [jira] Commented: (HADOOP-4539) Streaming Edits to a Backup Node.
Konstantin Shvachko 2010-12-18, 02:10
Hi Hari,

Could you please post questions to
[EMAIL PROTECTED]
Jiras are for tracking issues. This one is closed.

The answer to your question if I understood it correctly is that
there is no mechanism for fail over to BackupNode so far.

You can find more details about different types of nodes in hdfs
documentation:
http://hadoop.apache.org/hdfs/docs/current/hdfs_user_guide.html#Backup+Node
and recent paper:
http://storageconference.org/2010/Papers/MSST/Shvachko.pdf

Thanks,
--Konstantin
On Thu, Dec 16, 2010 at 11:12 PM, Hari A V (JIRA) <[EMAIL PROTECTED]> wrote:

>
>    [
> https://issues.apache.org/jira/browse/HADOOP-4539?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12972375#action_12972375]
>
> Hari A V commented on HADOOP-4539:
> ----------------------------------
>
> Hi,
> I am pretty new to Hadoop and HDFS. I was curious what happens to an
> incomplete file write.
> 1. Namenode Active and Standby running
> 2. From a client, i started copying 1 GB file
> 3. Around 500 MB is copied, while Primary Namenode goes down.
>
> Some how, if i make the standby name node to active and make the client to
> resumbit the request to the new Active name node, whether file copying will
> continue from where it is left or it will restart ?
>
> I am seeing some issues with acquiring of Lease in case of client
> requesting to the new Active name node. Can anyone please help me with this
> ?
>
> > Streaming Edits to a Backup Node.
> > ---------------------------------
> >
> >                 Key: HADOOP-4539
> >                 URL: https://issues.apache.org/jira/browse/HADOOP-4539
> >             Project: Hadoop Common
> >          Issue Type: New Feature
> >            Reporter: Konstantin Shvachko
> >            Assignee: Konstantin Shvachko
> >             Fix For: 0.21.0
> >
> >         Attachments: BackupNode.patch, BackupNode.patch,
> BackupNode.patch, BackupNode.patch, BackupNode.patch, BackupNode.patch,
> image001.gif, StreamEditsToBN.pdf, StreamEditsToSNN.htm
> >
> >
> > Currently Secondary name-node acts as mere checkpointer.
> > Secondary name-node should be transformed into a standby name-node (SNN).
> > The long term goal is to make it a warm standby.
> > The purpose of this issue is to provide real time streaming of edits to
> SNN so that it contained the up-to-date namespace state.
>
> --
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