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 HDFS architecture documentation of version 2.x is outdated about 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


Project: http://git-wip-us.apache.org/repos/asf/hadoop/repo
Commit: http://git-wip-us.apache.org/repos/asf/hadoop/commit/fc509f66
Tree: http://git-wip-us.apache.org/repos/asf/hadoop/tree/fc509f66
Diff: http://git-wip-us.apache.org/repos/asf/hadoop/diff/fc509f66

Branch: refs/heads/HDFS-7240
Commit: fc509f66d814e7a5ed81d5d73b23c400625d573b
Parents: 71566e2
Author: Akira Ajisaka <aajis...@apache.org>
Authored: Tue Aug 18 23:31:52 2015 +0900
Committer: Akira Ajisaka <aajis...@apache.org>
Committed: Tue Aug 18 23:31:52 2015 +0900

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 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(-)
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http://git-wip-us.apache.org/repos/asf/hadoop/blob/fc509f66/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 132adc1..3a7b816 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
+++ b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
@@ -1191,6 +1191,9 @@ 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 HDFS architecture documentation of version 2.x is outdated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/fc509f66/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 a30877a..aa94a2f 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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