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https://issues.apache.org/jira/browse/HDFS-11633?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15960838#comment-15960838
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Wei-Chiu Chuang commented on HDFS-11633:
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[~drankye]
bq. I saw you only added some test codes and am not clear how it would fix the
reported issue.
My bad. HDFS-11633.test.patch is the test code with no fix.
HDFS-11633.001.patch has a "fix" where it does not clear ECPM in
{{FSNamesystem.clear()}}.
bq. The enabled erasure coding policies are from a configuration and then
maintained in the ErasureCodingPolicyManager. You mean there is some case that
the policies can be cleared?
Correct. FSImage loading fallback is just one of the triggers. It looks like
other events could also lead to the same issue.
> FSImage loading fallback may disable all erasure coding policies
> -----------------------------------------------------------------
>
> Key: HDFS-11633
> URL: https://issues.apache.org/jira/browse/HDFS-11633
> Project: Hadoop HDFS
> Issue Type: Bug
> Components: erasure-coding, namenode
> Affects Versions: 3.0.0-alpha3
> Reporter: Wei-Chiu Chuang
> Assignee: Wei-Chiu Chuang
> Priority: Critical
> Labels: hdfs-ec-3.0-must-do
> Attachments: HDFS-11633.001.patch, HDFS-11633.test.patch
>
>
> If NameNode fails to load the fsimage in the first NameNode metadata
> directory, it accidentally clears all enabled erasure coding policies in
> ErasureCodingPolicyManager.
> Even if the NameNode configures multiple fsimage metadata directory and it
> successfully loads the second one, enabled erasure coding policies are not
> restored.
> In the current implementation, we do not have a ErasureCodingPolicyManager
> section in fsimage, so a fsimage reload does not reload ECPM.
> The easiest fix before ECPM section is implemented, is don't clear ECPM when
> FSNamesystem is cleared.
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