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https://issues.apache.org/jira/browse/HADOOP-4885?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12666032#action_12666032
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Boris Shkolnik commented on HADOOP-4885:
----------------------------------------
Another issue is testing. To test this feature we would need to simulate
failure to write into edit logs. For manual testing I used mounting.
But that may be non-portable to all the systems, so I need another solution.
My suggestions is to create a "mock" of the stream class. It will extend from
EditLogFileOutputStream and override write() methods.
It will also introduce a boolean member flag to specify if it is in a "failure"
mode. When the flag is set - the write methods will throw IOException, if not
they will call corresponding functions from the super classes.
Class will look something like this:
------------
class EditLogFileErrorTestOutputStream extends EditLogFileOutputStream {
private boolean throwException = false;
public void setThrowException(boolean val){
throwException = val;
}
public void write(int b) throws IOException {
if(throwException)
throw new IOException("Simulated IOException in write()");
else
super.write(b);
}
}
--------------
configuration will have a setting "dfs.name.dir.simulateError" to specify that
it needs editLog streams of the EditLogFileErrorTestOutputStream class.
> Try to restore failed replicas of Name Node storage (at checkpoint time)
> ------------------------------------------------------------------------
>
> Key: HADOOP-4885
> URL: https://issues.apache.org/jira/browse/HADOOP-4885
> Project: Hadoop Core
> Issue Type: Improvement
> Components: dfs
> Reporter: Boris Shkolnik
> Assignee: Boris Shkolnik
>
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