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From Allen Wittenauer <awittena...@linkedin.com>
Subject Re: Best way to reduce a 8-node cluster in half and get hdfs to come out of safe mode
Date Fri, 06 Aug 2010 15:53:09 GMT

On Aug 6, 2010, at 8:35 AM, He Chen wrote:

> Way#3
> 1) bring up all 8 dn and the nn
> 2) retire one of your 4 nodes:
>           kill the datanode process
>           hadoop dfsadmin -refreshNodes  (this should be done on nn)

No need to refresh nodes.  It only re-reads the dfs.hosts.* files.

> 3) do 2) extra three times

Depending upon what the bandwidth param is, this should theoretically take a significantly
longer time.  Since you need for the grid to get back to healthy before each kill.
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