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From Jayadev Jayaraman <>
Subject Re: vnodes on aws
Date Thu, 05 Dec 2013 23:31:44 GMT
Availability zones are analogous to racks not data centres . EC2 regions
are equivalent to data centres.

You can use vnodes if you want to deploy a cluster across multiple regions
(data centres) with one availability zone per region. Each region maintains
a separate ring.

I don't know if you can use vnodes on multiple rack topologies however. In
my case, Wlwe host a EC2 cluster with 2 fold replication and 2 zones in the
same region and we don't use vnodes
On Dec 5, 2013 2:32 PM, "Andrey Ilinykh" <> wrote:

> Hello everybody!
> We run cassandra 1.1 on ec2 instances. We use three availability zones,
> the replication factor is 3 also. NetworkTopologyStrategy guarantees each
> row is replicated in all availability zones. So, if we lost one zone quorum
> operations still work. We think about to upgrade to 1.2. Virtual nodes are
> the main reason. My understanding is - vnodes are distributed randomly, so
> their is no way to put every row into all availability zones.  Am I right?
> What would be the best way to deploy vnodes across several data centers
> (availability zones)?
> Thank you,
>   Andrey

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