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https://issues.apache.org/jira/browse/HDFS-2737?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13181725#comment-13181725
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Suresh Srinivas commented on HDFS-2737:
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My preference is not to do trigger editlog rollover for the purpose of HA. When
we undertook cleaning up editlog one of the things that was good about the
design was, NN could roll editlogs independently of the
backup/secondary/checkpointer. It became a local decision at the namenode. For
HA requiring an external trigger for editlog rolling is going back to previous
inflexibility. My preference is to read the editlog in progress and leave the
rolling of editlog as it is today, a local NN decision.
> HA: Automatically trigger log rolls periodically on the active NN
> -----------------------------------------------------------------
>
> Key: HDFS-2737
> URL: https://issues.apache.org/jira/browse/HDFS-2737
> Project: Hadoop HDFS
> Issue Type: Sub-task
> Components: ha, name-node
> Affects Versions: HA branch (HDFS-1623)
> Reporter: Todd Lipcon
> Assignee: Todd Lipcon
>
> Currently, the edit log tailing process can only read finalized log segments.
> So, if the active NN is not rolling its logs periodically, the SBN will lag a
> lot. This also causes many datanode messages to be queued up in the
> PendingDatanodeMessage structure.
> To combat this, the active NN needs to roll its logs periodically -- perhaps
> based on a time threshold, or perhaps based on a number of transactions. I'm
> not sure yet whether it's better to have the NN roll on its own or to have
> the SBN ask the active NN to roll its logs.
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