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https://issues.apache.org/jira/browse/HDFS-6184?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14110022#comment-14110022
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Hadoop QA commented on HDFS-6184:
---------------------------------
{color:red}-1 overall{color}. Here are the results of testing the latest
attachment
http://issues.apache.org/jira/secure/attachment/12664231/HDFS-6184.patch
against trunk revision .
{color:green}+1 @author{color}. The patch does not contain any @author
tags.
{color:green}+1 tests included{color}. The patch appears to include 1 new
or modified test files.
{color:green}+1 javac{color}. The applied patch does not increase the
total number of javac compiler warnings.
{color:green}+1 javadoc{color}. There were no new javadoc warning messages.
{color:green}+1 eclipse:eclipse{color}. The patch built with
eclipse:eclipse.
{color:green}+1 findbugs{color}. The patch does not introduce any new
Findbugs (version 2.0.3) warnings.
{color:green}+1 release audit{color}. The applied patch does not increase
the total number of release audit warnings.
{color:red}-1 core tests{color}. The patch failed these unit tests in
hadoop-common-project/hadoop-common hadoop-hdfs-project/hadoop-hdfs:
org.apache.hadoop.ipc.TestFairCallQueue
org.apache.hadoop.metrics2.impl.TestMetricsSystemImpl
org.apache.hadoop.ipc.TestIPC
org.apache.hadoop.ipc.TestCallQueueManager
The test build failed in
hadoop-hdfs-project/hadoop-hdfs
{color:green}+1 contrib tests{color}. The patch passed contrib unit tests.
Test results:
https://builds.apache.org/job/PreCommit-HDFS-Build/7756//testReport/
Console output: https://builds.apache.org/job/PreCommit-HDFS-Build/7756//console
This message is automatically generated.
> Capture NN's thread dump when it fails over
> -------------------------------------------
>
> Key: HDFS-6184
> URL: https://issues.apache.org/jira/browse/HDFS-6184
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: namenode
> Reporter: Ming Ma
> Assignee: Ming Ma
> Attachments: HDFS-6184.patch
>
>
> We have seen several false positives in terms of when ZKFC considers NN to be
> unhealthy. Some of these triggers unnecessary failover. Examples,
> 1. SBN checkpoint caused ZKFC's RPC call into NN timeout. The consequence
> isn't bad; just that SBN will quit ZK membership and rejoin it later. But it
> is unnecessary. The reason is checkpoint acquires NN global write lock and
> all rpc requests are blocked. Even though HAServiceProtocol.monitorHealth
> doesn't need to acquire NN lock; it still needs to user service rpc queue.
> 2. When ANN is busy, sometimes the global lock can block other requests.
> ZKFC's RPC call timeout. This will trigger failover. The question is even if
> after the failover, the new ANN might run into similar issue.
> We can increase ZKFC to NN timeout value to mitigate this to some degree. If
> ZKFC can be more accurate in judgment if NN is health or not and can predict
> the failover will help, that will be useful. For example, we can,
> 1. Have ZKFC made decision based on NN thread dump.
> 2. Have a dedicated rpc pool for ZKFC > NN. Given health check doesn't need
> to acquire NN global lock; so it can go through even if NN is doing
> checkpointing or very busy.
> Any comments?
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