Repository: hadoop
Updated Branches:
refs/heads/branch-2.7 2d1ff2e1c -> 139fd21c8
HADOOP-5323. Trash documentation should describe its directory structure and
configurations. Contributed by Weiwei Yang.
(cherry picked from commit 9a87f81ce6839d1b5ab3d663c1e82c7e572bdeb8)
Conflicts:
hadoop-hdfs-project/hadoop-hdfs/src/site/markdown/HdfsDesign.md
Project: http://git-wip-us.apache.org/repos/asf/hadoop/repo
Commit: http://git-wip-us.apache.org/repos/asf/hadoop/commit/139fd21c
Tree: http://git-wip-us.apache.org/repos/asf/hadoop/tree/139fd21c
Diff: http://git-wip-us.apache.org/repos/asf/hadoop/diff/139fd21c
Branch: refs/heads/branch-2.7
Commit: 139fd21c8383f7535de16ea4cd8e0e147f7a23e9
Parents: 2d1ff2e
Author: Tsuyoshi Ozawa <[email protected]>
Authored: Thu Sep 3 22:34:25 2015 +0900
Committer: Tsuyoshi Ozawa <[email protected]>
Committed: Thu Sep 3 22:39:12 2015 +0900
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hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt | 3 +++
.../hadoop-hdfs/src/site/markdown/HdfsDesign.md | 6 ++++--
2 files changed, 7 insertions(+), 2 deletions(-)
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http://git-wip-us.apache.org/repos/asf/hadoop/blob/139fd21c/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
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diff --git a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
index 2a41a9e..5c4e16e 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
+++ b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
@@ -10,6 +10,9 @@ Release 2.7.2 - UNRELEASED
HDFS-8659. Block scanner INFO message is spamming logs. (Yongjun Zhang)
+ HADOOP-5323. Trash documentation should describe its directory structure
and
+ configurations. (Weiwei Yang via ozawa)
+
OPTIMIZATIONS
HDFS-8722. Optimize datanode writes for small writes and flushes (kihwal)
http://git-wip-us.apache.org/repos/asf/hadoop/blob/139fd21c/hadoop-hdfs-project/hadoop-hdfs/src/site/markdown/HdfsDesign.md
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diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/site/markdown/HdfsDesign.md
b/hadoop-hdfs-project/hadoop-hdfs/src/site/markdown/HdfsDesign.md
index 30571c8..8f1d011 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/site/markdown/HdfsDesign.md
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/site/markdown/HdfsDesign.md
@@ -224,9 +224,11 @@ Space Reclamation
### File Deletes and Undeletes
-When a file is deleted by a user or an application, it is not immediately
removed from HDFS. Instead, HDFS first renames it to a file in the `/trash`
directory. The file can be restored quickly as long as it remains in `/trash`.
A file remains in `/trash` for a configurable amount of time. After the expiry
of its life in `/trash`, the NameNode deletes the file from the HDFS namespace.
The deletion of a file causes the blocks associated with the file to be freed.
Note that there could be an appreciable time delay between the time a file is
deleted by a user and the time of the corresponding increase in free space in
HDFS.
+When a file is deleted by a user or an application, it is not immediately
removed from HDFS. Instead, HDFS moves it to a trash directory (each user has
its own trash directory under `/user/<username>/.Trash`).
+The file can be restored quickly as long as it remains in trash. Most recent
deleted files are moved to the current trash directory
(`/user/<username>/.Trash/Current`), and in a configurable interval, HDFS
creates checkpoints (under `/user/<username>/.Trash/<date>`) for files in
current trash directory and deletes old checkpoints when they are expired.
+After the expiry of its life in trash, the NameNode deletes the file from the
HDFS namespace. The deletion of a file causes the blocks associated with the
file to be freed. Note that there could be an appreciable time delay between
the time a file is deleted by a user and the time of the corresponding increase
in free space in HDFS.
-A user can Undelete a file after deleting it as long as it remains in the
`/trash` directory. If a user wants to undelete a file that he/she has deleted,
he/she can navigate the `/trash` directory and retrieve the file. The `/trash`
directory contains only the latest copy of the file that was deleted. The
`/trash` directory is just like any other directory with one special feature:
HDFS applies specified policies to automatically delete files from this
directory. Current default trash interval is set to 0 (Deletes file without
storing in trash). This value is configurable parameter stored as
`fs.trash.interval` stored in core-site.xml.
+Currently, the trash feature is disabled by default (deleting files without
storing in trash). User can enable this feature by setting a value greater than
zero for parameter `fs.trash.interval` (in core-site.xml). This value tells the
NameNode how long a checkpoint will be expired and removed from HDFS. In
addition, user can configure an appropriate time to tell NameNode how often to
create checkpoints in trash (the parameter stored as
`fs.trash.checkpoint.interval` in core-site.xml), this value should be smaller
or equal to fs.trash.interval.
### Decrease Replication Factor
