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From Sameer Farooqui <cassandral...@gmail.com>
Subject Does anybody have experience with running Cassandra in Amazon's Virtual Private Cloud (VPC)?
Date Thu, 05 May 2011 21:21:11 GMT
Here is an image that shows what the Amazon VPC we're thinking about using
looks like:

http://i.imgur.com/OUe1i.png


We would like to configure a 2 node Cassandra cluster in the private subnet
and a read/write web application service in the public subnet. However, we
also want to span the Cassandra cluster across from the Virginia VPC to a
California VPC and have 2 Cassandra nodes in the private subnet in Virginia
and 1 node in the private subnet in California.


Amazon states that EC2 instances in Virginia’s VPC can communicate with EC2
instances in California’s VPC as long as all communication takes place over
the internet gateway of each VPC and uses Elastic IP addresses as the
specified source or destination address.



But Amazon also says that “EIP addresses should only be used on instances in
subnets configured to route their traffic directly to the Internet Gateway”.
So, by this they must mean the public subnet in the diagram above. Amazon
goes on to say “EIPs cannot be used on instances in subnets configured to
use a NAT instance to access the Internet.”



It looks like we cannot have a Cassandra cluster spanning two Private
Subnets in two different regions. Can somebody with VPC experience confirm
this?


Also has anybody successfully deployed a Cassandra cluster in private
subnets spanning multiple regions? Any tips from your experience? How did
you find the latency over VPCs and gateways across regions?



- Sameer

Accenture Technology Labs

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