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Posted to common-commits@hadoop.apache.org by we...@apache.org on 2019/11/12 19:41:29 UTC
[hadoop] branch branch-3.1 updated: HDFS-14959: [SBNN read] access
time should be turned off (#1706) Contributed by Chao Sun.
This is an automated email from the ASF dual-hosted git repository.
weichiu pushed a commit to branch branch-3.1
in repository https://gitbox.apache.org/repos/asf/hadoop.git
The following commit(s) were added to refs/heads/branch-3.1 by this push:
new 7e0f1ea HDFS-14959: [SBNN read] access time should be turned off (#1706) Contributed by Chao Sun.
7e0f1ea is described below
commit 7e0f1eabd8f40a2921a9a8fd95dd7032c3d72719
Author: Chao Sun <su...@apache.org>
AuthorDate: Tue Nov 12 11:35:50 2019 -0800
HDFS-14959: [SBNN read] access time should be turned off (#1706) Contributed by Chao Sun.
(cherry picked from commit 97ec34e117af71e1a9950b8002131c45754009c7)
(cherry picked from commit 0c12d633b9797f2cb14246fe020993b2e9123e82)
---
.../hadoop-hdfs/src/site/markdown/ObserverNameNode.md | 15 +++++++++++++++
1 file changed, 15 insertions(+)
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/site/markdown/ObserverNameNode.md b/hadoop-hdfs-project/hadoop-hdfs/src/site/markdown/ObserverNameNode.md
index af1569c..2422f8c 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/site/markdown/ObserverNameNode.md
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/site/markdown/ObserverNameNode.md
@@ -194,6 +194,21 @@ few configurations to your **hdfs-site.xml**:
<value>1048576</value>
</property>
+* **dfs.namenode.accesstime.precision** -- whether to enable access
+ time for HDFS file.
+
+ It is **highly recommended** to disable this configuration. If
+ enabled, this will turn a `getBlockLocations` call into a write call,
+ as it needs to hold write lock to update the time for the opened
+ file. Therefore, the request will fail on all Observer NameNodes and fall
+ back to the active eventually. As result, RPC performance will degrade.
+
+ <property>
+ <name>dfs.namenode.accesstime.precision</name>
+ <value>0</value>
+ </property>
+
+
### New administrative command
A new HA admin command is introduced to transition a Standby NameNode
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