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From Michael Segel <michael_se...@hotmail.com>
Subject Re: Regions and Rowkeys
Date Mon, 11 May 2015 22:55:26 GMT
Why would you expect to have a region allocated to all of the region servers? 
You generate a region based on either pre-splitting (you set the region’s key range) , or
you start with one region and grow from there. 

Please read either Lars George’s book (dated) or Nick Dimiduk’s book. 
(Sorry but has Lars George ever done a second or third edition yet? ) 

> On May 11, 2015, at 5:38 PM, Arun Patel <arunp.bigdata@gmail.com> wrote:
> I have some basic questions on regions.
> 1) I have a 10 node HBase cluster.  When I create a table in HBase, how
> many regions will be allocated by default?  I looked at the HBase Master UI
> and it seems regions are not allocated to all the Regionservers by
> default.  How can I allocate the regions in all Region Servers?  Basically,
> This distributes the data in a better way If I am using a slated key. My
> requirement is to distribute the data across the cluster using salted
> keys.  But, Having few regions is a constraint?
> 2) How does the rowkey to region mapping works?  In Cassandra, we have a
> concept of assigning token range for each node.  Rowkey will be assigned to
> a node based on the token range.  How does this work in HBase?
> Regards,
> Arun

The opinions expressed here are mine, while they may reflect a cognitive thought, that is
purely accidental. 
Use at your own risk. 
Michael Segel
michael_segel (AT) hotmail.com

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