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From Alain RODRIGUEZ <>
Subject Re: Ec2Snitch to Ec2MultiRegionSnitch
Date Tue, 23 Apr 2013 07:26:49 GMT
Hi,these advice are very welcome.

@Dane, about the rack awareness, we use only one rack per DC, so I guess
using EC2MultiRegionSnitch will do just fine and it doesn't need any
configuration. Does it seem right to you. If we are someday interested on
multi racks I will make sure to use them properly. Thank you for this
insight anyway. You are advising me to test it, what would be a good way of
testing it (I can use AWS EC2 instances if needed) ?


"I recommend using the same number of nodes in both DC's."

Why ? I mean we have maybe only 5% of our customers on the us-east zone,
what in C* require to have the same number of node on each DC ?

"Add the nodes (I recommend 6) with auto_bootstrap: false added to the yaml.
update the keyspace replication strategy to add rf:3 for the new DC.
Use nodetool rebuild on the new nodes to rebuild them from the us-west DC. "

What is better on adding nodes with no data and then rebuild them compared
to using the auto_bootstrap ?

"I prefer to use the offset method. Take the 6 tokens from your us-west DC
and add 100 to them for the new dc. "

Any doc on this ? I am not aware of all the possibilities. Why is this the
best method according to you ?

About seeds => "Yes. Have 3 from each."

What is the point of this ?

I didn't thought this change would be that tricky, thank you guys for these
warnings and your help ;)


2013/4/23 Dane Miller <>

> On Thu, Apr 18, 2013 at 7:41 AM, Alain RODRIGUEZ <>
> wrote:
> > I am wondering about the process to grow from one data center to a few of
> > them. First thing is we use EC2Snitch for now. So I guess we have to
> switch
> > to Ec2MultiRegionSnitch.
> >
> > c/ I am using the SimpleStrategy. Is it worth it/mandatory to change this
> > strategy when using multiple DC ?
> I suggest you thoroughly read the datastax documentation on cassandra
> replication.  The change you are planning is big - make sure to try it
> in a test environment first.  Also, you might find you don't really
> need Cassandra's rack aware feature, and can operate using
> (Gossiping)PropertyFileSnitch.  The rack feature is listed as an
> "anti-pattern" here:
> Here are some recent discussions on this list:
> Dane

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