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From William Oberman <>
Subject Re: how to migrate?
Date Fri, 26 Aug 2011 01:31:45 GMT
>  create keyspace civicscience with replication_factor=3 and
> strategy_options = [{us-east:3}] and
> placement_strategy='org.apache.cassandra.locator.NetworkTopologyStrategy';
> FYI the replication_factor property with the NTS is incorrect, the next(?)
> revision of 0.8 will raise an error on restart.

I'm not sure what you're saying.  Should it have been:
create keyspace civicscience with strategy_options = [{us-east:3}] and

> I'm wondering if I write my own snitch that extends Ec2Snitch with
> overrides as follows:
> getDC = if(AZ == c || d) return return us-east (to keep current nodes the
> same) else return us-east-hadoop;
> getRack = return super(); (returning a,b,c,d seems ok)
> prob easier to use the PropertyFileSnitch, see the yaml file and the
> conf/ . You can then manually put the nodes
> into the DC and Rack you want.

I'll read up on them next then.  The Ec2Snitch seemed tempting to use, given
I was in Ec2 ;-)

>  -Can I (how do I safely) change the keyspace strategy_options
> from [{us-east:3}] to [{us-east:2, us-east-hadoop:1}]   This seems like
> the riskiest/most complicated step of everything I've proposed...

The wiki has changed since I last read it (I guess that happens) ;-)  I
think I understand how to make changes and migrate data around now.

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