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https://issues.apache.org/jira/browse/HDFS-5754?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13885317#comment-13885317
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Tsz Wo (Nicholas), SZE commented on HDFS-5754:
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- In DataStorage, BPServiceActor and BlockPoolSliceStorage, it should not
compare DATANODE_LAYOUT_VERSION with nsInfo.getLayoutVersion() anymore.
- Map<Integer, TreeSet<LayoutFeature>> should be Map<Integer,
Set<LayoutFeature>>. We should declear with interface Set (or should we use
SortedSet?) instead of particular implementation TreeSet.
- In PBHelper, could we use null (i.e. unknown) instead of NodeType.NAME_NODE
as default? Or we could add a setStorageType(NodeType) method so that we could
set it when it is null.
- The type parameter below is not used. Should it be removed?
{code}
//Storage.java
protected Storage(NodeType type, StorageInfo storageInfo) {
super(storageInfo);
- this.storageType = type;
}
{code}
- I suggest to move the layout version related code out from NameNode and
DataNode to new classes, say NameNodeLayoutVersion and DataNodeLayoutVersion.
> 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
> 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
>
>
> 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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