hadoop-hdfs-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Daryn Sharp (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HDFS-2139) Fast copy for HDFS.
Date Fri, 02 May 2014 18:29:27 GMT

    [ https://issues.apache.org/jira/browse/HDFS-2139?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13988059#comment-13988059

Daryn Sharp commented on HDFS-2139:

I glanced through the patch but haven't studied it.  Initial questions:
# Are block tokens being checked for this operation?
# Does the DN enforce no linking of UC blocks?

> Fast copy for HDFS.
> -------------------
>                 Key: HDFS-2139
>                 URL: https://issues.apache.org/jira/browse/HDFS-2139
>             Project: Hadoop HDFS
>          Issue Type: New Feature
>            Reporter: Pritam Damania
>         Attachments: HDFS-2139.patch
>   Original Estimate: 168h
>  Remaining Estimate: 168h
> There is a need to perform fast file copy on HDFS. The fast copy mechanism for a file
works as
> follows :
> 1) Query metadata for all blocks of the source file.
> 2) For each block 'b' of the file, find out its datanode locations.
> 3) For each block of the file, add an empty block to the namesystem for
> the destination file.
> 4) For each location of the block, instruct the datanode to make a local
> copy of that block.
> 5) Once each datanode has copied over its respective blocks, they
> report to the namenode about it.
> 6) Wait for all blocks to be copied and exit.
> This would speed up the copying process considerably by removing top of
> the rack data transfers.
> Note : An extra improvement, would be to instruct the datanode to create a
> hardlink of the block file if we are copying a block on the same datanode

This message was sent by Atlassian JIRA

View raw message