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From Kai Voigt...@123.org>
Subject Re: about rack awareness
Date Fri, 04 Jul 2014 03:43:59 GMT
Rack Awareness actually should be called Switch Awareness, and that’s what people typically
do: Nodes in a rack are at the same switch, also you should have balanced capacity across
racks/switches for a balanced distribution.

So you definitely want to rearrange your setup, especially if your cluster grows larger.


Am 04.07.2014 um 03:31 schrieb sunww <spesun@outlook.com>:

> Hi
> I have two questions about rack awareness.
> 1、I installed a hadoop2.2 , hbase0.96 cluster, which have 2 racks. 
> rack1 have 10 machines , rack2 have 5 machines. Because of 3 replicas, rack2 will store
more data then rack1.
> Maybe I need to move some machines from  rack2 to rack1?
> If I had more racks, only one have 5 machines and the others have 10 machines, Will data
unbalance more serious? 
> 2、If some racks share the same  power and switch, is rack awareness necessary ?
> Thanks 

Kai Voigt			Am Germaniahafen 1			k@123.org
					24143 Kiel					+49 160 96683050
					Germany						@KaiVoigt

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