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https://issues.apache.org/jira/browse/HDFS-2001?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Todd Lipcon updated HDFS-2001:
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Component/s: name-node
Description:
In the old design for edits/image storage, the secondary namenode does a
complicated dance of moving "current/" to "lastcheckpoint.tmp", checkpointing
into "current/", then moving "lastcheckpoint.tmp" back to
"previous.checkpoint". The idea here was so that there would always be one
directory with a valid set of storage files.
In the HDFS-1073 design, this complicated dance isn't necessary. If a
checkpoint fails, we can just rm that single fsimage_N.ckpt file and still be
left with a valid storage directory.
So, we can just let the 2NN keep a single current/ dir around for all
checkpoints and eliminate the complexity of the dance.
Affects Version/s: Edit log branch (HDFS-1073)
Fix Version/s: Edit log branch (HDFS-1073)
> HDFS-1073: Kill previous.checkpoint, lastcheckpoint.tmp directories
> -------------------------------------------------------------------
>
> Key: HDFS-2001
> URL: https://issues.apache.org/jira/browse/HDFS-2001
> Project: Hadoop HDFS
> Issue Type: Sub-task
> Components: name-node
> Affects Versions: Edit log branch (HDFS-1073)
> Reporter: Todd Lipcon
> Assignee: Todd Lipcon
> Fix For: Edit log branch (HDFS-1073)
>
>
> In the old design for edits/image storage, the secondary namenode does a
> complicated dance of moving "current/" to "lastcheckpoint.tmp", checkpointing
> into "current/", then moving "lastcheckpoint.tmp" back to
> "previous.checkpoint". The idea here was so that there would always be one
> directory with a valid set of storage files.
> In the HDFS-1073 design, this complicated dance isn't necessary. If a
> checkpoint fails, we can just rm that single fsimage_N.ckpt file and still be
> left with a valid storage directory.
> So, we can just let the 2NN keep a single current/ dir around for all
> checkpoints and eliminate the complexity of the dance.
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