[
https://issues.apache.org/jira/browse/HDFS-3370?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13293480#comment-13293480
]
Lars Hofhansl commented on HDFS-3370:
-------------------------------------
Thanks Liyin. Sounds good.
One thought that occurred to me since: We need to think about copy semantics.
For example how will distcp handle this? It shouldn't create a new copy of a
file for each hardlink that points to it, but rather just copy it at most once
and create hardlinks for each following reference. But then what about multiple
distcp commands that happen to cover hardlinks to the same file? I suppose in
the case we cannot be expected to avoid multiple copies of the same file (but
at most one copy for each invocation of distcp, and only if the distcp happens
to cover a different hardlink).
> HDFS hardlink
> -------------
>
> Key: HDFS-3370
> URL: https://issues.apache.org/jira/browse/HDFS-3370
> Project: Hadoop HDFS
> Issue Type: New Feature
> Reporter: Hairong Kuang
> Assignee: Liyin Tang
> Attachments: HDFS-HardLink.pdf
>
>
> We'd like to add a new feature hardlink to HDFS that allows harlinked files
> to share data without copying. Currently we will support hardlinking only
> closed files, but it could be extended to unclosed files as well.
> Among many potential use cases of the feature, the following two are
> primarily used in facebook:
> 1. This provides a lightweight way for applications like hbase to create a
> snapshot;
> 2. This also allows an application like Hive to move a table to a different
> directory without breaking current running hive queries.
--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators:
https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa
For more information on JIRA, see: http://www.atlassian.com/software/jira
