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https://issues.apache.org/jira/browse/HDFS-6440?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14243070#comment-14243070
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Lei (Eddy) Xu commented on HDFS-6440:
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[~jesse_yates] Thank you very much for your answers! It looks great.
I only have one minor question left:
bq. This was the idea behind adding the 'primary checkpointer' logic.
And in the design doc,
bq. When a SNN (or just Standby Checkpoint node) successfully completes a
checkpoint, it marks itself internally as the ‘primary check pointer’;
Does this mean that there might be multiple SNNs marking themselves as 'primary
checkpointer' during the same time period, since it is determined by SNN
itself? Would it result multiple SNNs uploading fsimages with small deltas in
some rare scenarios? Would it be reasonable to also let ANN to reject fsimage
upload request?
> Support more than 2 NameNodes
> -----------------------------
>
> Key: HDFS-6440
> URL: https://issues.apache.org/jira/browse/HDFS-6440
> Project: Hadoop HDFS
> Issue Type: New Feature
> Components: auto-failover, ha, namenode
> Affects Versions: 2.4.0
> Reporter: Jesse Yates
> Assignee: Jesse Yates
> Attachments: Multiple-Standby-NameNodes_V1.pdf,
> hdfs-6440-cdh-4.5-full.patch, hdfs-multiple-snn-trunk-v0.patch
>
>
> Most of the work is already done to support more than 2 NameNodes (one
> active, one standby). This would be the last bit to support running multiple
> _standby_ NameNodes; one of the standbys should be available for fail-over.
> Mostly, this is a matter of updating how we parse configurations, some
> complexity around managing the checkpointing, and updating a whole lot of
> tests.
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