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From Steve Loughran <ste...@hortonworks.com>
Subject Re: How to change topology
Date Tue, 09 Oct 2012 08:22:50 GMT
On 8 October 2012 14:23, Shinichi Yamashita <shin1.ym@gmail.com> wrote:

> Hi,
> I know that DataNode and TaskTracker must restart to change topology.

no, it's the Namenode and JobTracker that needs to be restarted; they are
the bits that care where the boxes are.

> Is there the method to execute the topology change without restart of
> DataNode and TaskTracker?
> In other words, can I change the topology by a command?

No -the map gets cached, and when the services start up they do quick check
to see if the topology is flat or spread across switches -and use that flag
to make various placement decisions.


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