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https://issues.apache.org/jira/browse/HDFS-5754?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13887540#comment-13887540
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Vinay commented on HDFS-5754:
-----------------------------
First of all, sorry for coming in late ( that too after commit )...
All Changes look good, except following one.
{noformat}+ if (DataNodeLayoutVersion.supports(
+ LayoutVersion.Feature.FEDERATION,
+ HdfsConstants.DATANODE_LAYOUT_VERSION) &&
+ HdfsConstants.DATANODE_LAYOUT_VERSION == nsInfo.getLayoutVersion()) {
readProperties(sd, nsInfo.getLayoutVersion());
writeProperties(sd);
LOG.info("Layout version rolled back to " +{noformat}
Here while rolling back and previous directory not exist,
{{DATANODE_LAYOUT_VERSION}} is directly compared with
{{NAMENODE_LAYOUT_VERSION}} to update the VERSION file.
But LayoutVersion is split because both these could be different in same
version of hadoop right?
{noformat}+ if (HdfsConstants.DATANODE_LAYOUT_VERSION !=
nsInfo.getLayoutVersion()) {
+ LOG.info("DataNode and NameNode layout versions are different:" +
+ " DataNode version: "+ HdfsConstants.DATANODE_LAYOUT_VERSION +
+ " NameNode version: "+ nsInfo.getLayoutVersion());{noformat}
May be this log not required. Only below log is enough with condition removed.
{noformat}+ if( HdfsConstants.DATANODE_LAYOUT_VERSION ==
nsInfo.getLayoutVersion())
+ LOG.info("Data-node version: " + HdfsConstants.DATANODE_LAYOUT_VERSION +
+ " and name-node layout version: " + nsInfo.getLayoutVersion());{noformat}
If any changes required I am ok to do in separate Jira instead of re-opening
this.
> Split LayoutVerion into NamenodeLayoutVersion and DatanodeLayoutVersion
> ------------------------------------------------------------------------
>
> Key: HDFS-5754
> URL: https://issues.apache.org/jira/browse/HDFS-5754
> Project: Hadoop HDFS
> Issue Type: Sub-task
> Components: datanode, namenode
> Reporter: Tsz Wo (Nicholas), SZE
> Assignee: Brandon Li
> Fix For: HDFS-5535 (Rolling upgrades)
>
> Attachments: FeatureInfo.patch, HDFS-5754.001.patch,
> HDFS-5754.002.patch, HDFS-5754.003.patch, HDFS-5754.004.patch,
> HDFS-5754.006.patch, HDFS-5754.007.patch, HDFS-5754.008.patch,
> HDFS-5754.009.patch, HDFS-5754.010.patch, HDFS-5754.012.patch,
> HDFS-5754.013.patch
>
>
> Currently, LayoutVersion defines the on-disk data format and supported
> features of the entire cluster including NN and DNs. LayoutVersion is
> persisted in both NN and DNs. When a NN/DN starts up, it checks its
> supported LayoutVersion against the on-disk LayoutVersion. Also, a DN with a
> different LayoutVersion than NN cannot register with the NN.
> We propose to split LayoutVersion into two independent values that are local
> to the nodes:
> - NamenodeLayoutVersion - defines the on-disk data format in NN, including
> the format of FSImage, editlog and the directory structure.
> - DatanodeLayoutVersion - defines the on-disk data format in DN, including
> the format of block data file, metadata file, block pool layout, and the
> directory structure.
> The LayoutVersion check will be removed in DN registration. If
> NamenodeLayoutVersion or DatanodeLayoutVersion is changed in a rolling
> upgrade, then only rollback is supported and downgrade is not.
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