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From James Brown <jb...@syndicate.net>
Subject Re: OK to run data node on same machine as secondary name node?
Date Wed, 15 Aug 2012 23:06:22 GMT
It is ok as long as the Secondary NameNode runs on a machine physically 
separate from the NameNode.

Make sure the fs.checkpoint.dir and fs.checkpoint.edit.dir directory 
lists have multiple physical devices in each.


On 8/15/2012 3:11 PM, David Rosenstrauch wrote:
> I have a Hadoop cluster that's a little tight on resources.  I was
> thinking one way I could solve this could be by running an additional
> data node on the same machine as the secondary name node.
>
> I wouldn't dare do that on the primary name node, since that machine
> needs to be extremely performant.  But since all the secondary name node
> does is doing a merge of the name node's checkpoint and logs, which is
> not an activity that require top-notch real-time performance, I thought
> it might not be a problem if I were to set up a data node running there
> as well.
>
> Any reasons why that might be a bad idea?
>
> Thanks,
>
> DR
>


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