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From aajis...@apache.org
Subject hadoop git commit: HDFS-8852. HDFS architecture documentation of version 2.x is outdated about append write support. Contributed by Ajith S.
Date Tue, 18 Aug 2015 14:36:20 GMT
Repository: hadoop
Updated Branches:
  refs/heads/branch-2.7 d610144d4 -> f98b5ae3b


HDFS-8852. HDFS architecture documentation of version 2.x is outdated about append write support.
Contributed by Ajith S.

(cherry picked from commit fc509f66d814e7a5ed81d5d73b23c400625d573b)
(cherry picked from commit 38b344adfa7a0e57cad8931fb5c699ad4d48150f)


Project: http://git-wip-us.apache.org/repos/asf/hadoop/repo
Commit: http://git-wip-us.apache.org/repos/asf/hadoop/commit/f98b5ae3
Tree: http://git-wip-us.apache.org/repos/asf/hadoop/tree/f98b5ae3
Diff: http://git-wip-us.apache.org/repos/asf/hadoop/diff/f98b5ae3

Branch: refs/heads/branch-2.7
Commit: f98b5ae3bb8d4ecc0940a63ced9341f3d76148f1
Parents: d610144
Author: Akira Ajisaka <aajisaka@apache.org>
Authored: Tue Aug 18 23:31:52 2015 +0900
Committer: Akira Ajisaka <aajisaka@apache.org>
Committed: Tue Aug 18 23:33:28 2015 +0900

----------------------------------------------------------------------
 hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt                     | 3 +++
 hadoop-hdfs-project/hadoop-hdfs/src/site/markdown/HdfsDesign.md | 2 +-
 2 files changed, 4 insertions(+), 1 deletion(-)
----------------------------------------------------------------------


http://git-wip-us.apache.org/repos/asf/hadoop/blob/f98b5ae3/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
----------------------------------------------------------------------
diff --git a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
index b35cc05..0f9d0c7 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
+++ b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
@@ -22,6 +22,9 @@ Release 2.7.2 - UNRELEASED
     HDFS-8806. Inconsistent metrics: number of missing blocks with replication
     factor 1 not properly cleared. (Zhe Zhang via aajisaka)
 
+    HDFS-8852. HDFS architecture documentation of version 2.x is outdated
+    about append write support. (Ajith S via aajisaka)
+
 Release 2.7.1 - 2015-07-06
 
   INCOMPATIBLE CHANGES

http://git-wip-us.apache.org/repos/asf/hadoop/blob/f98b5ae3/hadoop-hdfs-project/hadoop-hdfs/src/site/markdown/HdfsDesign.md
----------------------------------------------------------------------
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 87a9fcd..30571c8 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/site/markdown/HdfsDesign.md
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/site/markdown/HdfsDesign.md
@@ -73,7 +73,7 @@ Applications that run on HDFS have large data sets. A typical file in HDFS
is gi
 
 ### Simple Coherency Model
 
-HDFS applications need a write-once-read-many access model for files. A file once created,
written, and closed need not be changed. This assumption simplifies data coherency issues
and enables high throughput data access. A Map/Reduce application or a web crawler application
fits perfectly with this model. There is a plan to support appending-writes to files in the
future.
+HDFS applications need a write-once-read-many access model for files. A file once created,
written, and closed need not be changed except for appends and truncates. Appending the content
to the end of the files is supported but cannot be updated at arbitrary point. This assumption
simplifies data coherency issues and enables high throughput data access. A MapReduce application
or a web crawler application fits perfectly with this model.
 
 ### "Moving Computation is Cheaper than Moving Data"
 


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