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MapReduce >> mail # user >> Question about Name Spaces…

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Re: Question about Name Spaces…
Namespace divides are designed with application-level separation in
mind. Sharing a file across namespaces does not make a whole lot of
sense to me.

Anyhow, the data is on the same set of DNs, and there's HA for NN's
own availability (if thats really a concern), so I don't see why
anyone would like to _maintain_ two synced copies of files as thats
just data duplication when all you need is a simple path (viewfs)/URI
(hdfs) to access a file lying on a different NN.

The reason you mention of metadata availability doesn't sound logical
- in such a case a person has to build a self failover of URIs for
said file, which they can simply avoid by using HDFS HA for the
hosting NN.

On Wed, May 15, 2013 at 7:47 PM, Michael Segel
> Quick question...
> So when we have a cluster which has multiple namespaces (multiple name nodes) , why would you have a file in two different namespaces?

Harsh J