From 0191a862a36453170358726da114b6bf7ec3e169 Mon Sep 17 00:00:00 2001
From: Lei Xu <lei@apache.org>
Date: Fri, 15 Dec 2017 10:20:29 -0800
Subject: [PATCH] HDFS-12927. Update erasure coding doc to address unsupported
 APIs. (Contributed by Lei (Eddy) Xu)

(cherry picked from commit 949be14b0881186d76c3b60ee2f39ce67dc1654c)
---
 .../hadoop-hdfs/src/site/markdown/HDFSErasureCoding.md     | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/site/markdown/HDFSErasureCoding.md b/hadoop-hdfs-project/hadoop-hdfs/src/site/markdown/HDFSErasureCoding.md
index a884ed83905..4459c9475f7 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/site/markdown/HDFSErasureCoding.md
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/site/markdown/HDFSErasureCoding.md
@@ -220,11 +220,14 @@ Below are the details about each command.
 Limitations
 -----------
 
-Certain HDFS file write operations, i.e., `hflush`, `hsync` and `append`,
+Certain HDFS operations, i.e., `hflush`, `hsync`, `concat`, `setReplication`, `truncate` and `append`,
 are not supported on erasure coded files due to substantial technical
 challenges.
 
-* `append()` on an erasure coded file will throw `IOException`.
+* `append()` and `truncate()` on an erasure coded file will throw `IOException`.
+* `concat()` will throw `IOException` if files are mixed with different erasure
+coding policies or with replicated files.
+* `setReplication()` is no-op on erasure coded files.
 * `hflush()` and `hsync()` on `DFSStripedOutputStream` are no-op. Thus calling
 `hflush()` or `hsync()` on an erasure coded file can not guarantee data
 being persistent.