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Daryn Sharp commented on HDFS-3370: ----------------------------------- @Sanjay: Good point about simply recording length. It would eschew random-write (not proposing it, only mentioning since it was cited earlier), but a feature like that would require significant other changes so integration with hardlinks could be deferred until if/when that's implemented. If snapshots are implemented using COW-hardlinks, then we should consider duplicating the inode to preserve all metadata, ie. not just length at the time of snapshot. > 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