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https://issues.apache.org/jira/browse/HADOOP-1762?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12526648
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Konstantin Shvachko commented on HADOOP-1762:
---------------------------------------------
Mostly cosmetic comments:
# Datanode.setNewStorageID():
{code} } catch (UnknownHostException ignored) {} {code}
Should not be ignored but rather logged.
# We should deprecate FSEdits.OP_DATANODE_ADD and FSEdits.OP_DATANODE_REMOVE
so that we could eventually remove them sometimes.
# FSNamesystem.registerDatanode():
{code}
NameNode.stateChangeLog.info( "BLOCK* NameSystem.registerDatanode: "
+ "node " + nodeS.getName()
+ " is replaced by " + nodeReg.getName() +
" since they have the same storageID " +
nodeReg.getStorageID() +
". If this message repeats, both nodes " +
"might have same storageID by random " +
"chance. You need to restart one of the "
+
"nodes with its data cleared. ");
{code}
This message may cause confusion in the regular case.
The possibility of storage id collision is so negligible that we should not
hint on it every time one node *_legally_* replaces another with the same
storage id.
Let's retain the original redaction.
> Namenode does not need to store storageID and datanodeID persistently
> ---------------------------------------------------------------------
>
> Key: HADOOP-1762
> URL: https://issues.apache.org/jira/browse/HADOOP-1762
> Project: Hadoop
> Issue Type: Improvement
> Components: dfs
> Affects Versions: 0.14.0
> Reporter: Raghu Angadi
> Assignee: Raghu Angadi
> Attachments: HADOOP-1762-Opt2.patch, HADOOP-1762-Opt2.patch,
> HADOOP-1762-Opt2.patch, HADOOP-1762-Opt2.patch, HADOOP-1762.patch
>
>
> Currently Namenode stores all the storage-ids it generates since the
> beginning (since last format). It allocates a new storageID everytime a new
> datanode comes online. It also stores all the known datanode ids since the
> beginning.
> It would be better if Namenode did not have to keep track of these. I will
> describe a proposal in the next comment.
> This has implecations regd how Namenode helps administrators identify 'dead
> datanodes' etc. These issues are addressed in HADOOP-1138.
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