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https://issues.apache.org/jira/browse/HDFS-5869?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13892834#comment-13892834
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Jing Zhao commented on HDFS-5869:
---------------------------------
bq. we should disable the checkpointing from StandbyCheckpointer in StandbyNN
when RollingUpgrade in progress
Once we have HDFS-5889, we do not need to disable the checkpointing in SBN
anymore.
For the following code:
{code}
+ if (totalEdits > 1) {
+ // save namespace if this is not the second edit transaction
+ // (the first must be OP_START_LOG_SEGMENT)
+ fsNamesys.getFSImage().saveNamespace(fsNamesys);
+ }
{code}
My understand is that: if we have successfully done the checkpoint for the
startRollingUpgrade call, we will have an fsimage and in case that this is the
latest fsimage, we do not need to do the checkpoint again while restarting. But
if the fsimage is lost or this is the SBN/SNN, this extra checkpoint can be
triggered. Do I understand correctly here? And I guess the SecondaryNN actually
does not need to do this extra checkpoint?
> When rolling upgrade is in progress, NN should only create checkpoint right
> before the upgrade marker
> -----------------------------------------------------------------------------------------------------
>
> Key: HDFS-5869
> URL: https://issues.apache.org/jira/browse/HDFS-5869
> Project: Hadoop HDFS
> Issue Type: Sub-task
> Components: namenode
> Reporter: Tsz Wo (Nicholas), SZE
> Assignee: Tsz Wo (Nicholas), SZE
> Attachments: h5869_20140204.patch, h5869_20140204b.patch,
> h5869_20140205.patch
>
>
> - When starting rolling upgrade, NN should create a checkpoint before it
> writes the upgrade marker edit log transaction.
> - When rolling upgrade is in progress, NN should reject saveNamespace rpc
> calls. Further, if NN restarts, it should create a checkpoint only right
> before the upgrade marker.
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