[
https://issues.apache.org/jira/browse/HDFS-3107?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14791779#comment-14791779
]
Konstantin Shvachko commented on HDFS-3107:
-------------------------------------------
I would say absolutely go for it. As that was one of the motivations for
truncate to support nfs and fuse apis.
Let's check with the authors what is the state of nfs with respect to truncate.
[~brandonli] could you please elaborate.
> HDFS truncate
> -------------
>
> Key: HDFS-3107
> URL: https://issues.apache.org/jira/browse/HDFS-3107
> Project: Hadoop HDFS
> Issue Type: New Feature
> Components: datanode, namenode
> Reporter: Lei Chang
> Assignee: Plamen Jeliazkov
> Fix For: 2.7.0
>
> Attachments: HDFS-3107-13.patch, HDFS-3107-14.patch,
> HDFS-3107-15.patch, HDFS-3107-HDFS-7056-combined.patch, HDFS-3107.008.patch,
> HDFS-3107.15_branch2.patch, HDFS-3107.patch, HDFS-3107.patch,
> HDFS-3107.patch, HDFS-3107.patch, HDFS-3107.patch, HDFS-3107.patch,
> HDFS-3107.patch, HDFS-3107.patch, HDFS-3107.patch, HDFS-3107.patch,
> HDFS-3107.patch, HDFS_truncate.pdf, HDFS_truncate.pdf, HDFS_truncate.pdf,
> HDFS_truncate.pdf, HDFS_truncate_semantics_Mar15.pdf,
> HDFS_truncate_semantics_Mar15.pdf, HDFS_truncate_semantics_Mar21.pdf,
> HDFS_truncate_semantics_Mar21.pdf, editsStored, editsStored.xml
>
> Original Estimate: 1,344h
> Remaining Estimate: 1,344h
>
> Systems with transaction support often need to undo changes made to the
> underlying storage when a transaction is aborted. Currently HDFS does not
> support truncate (a standard Posix operation) which is a reverse operation of
> append, which makes upper layer applications use ugly workarounds (such as
> keeping track of the discarded byte range per file in a separate metadata
> store, and periodically running a vacuum process to rewrite compacted files)
> to overcome this limitation of HDFS.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
