My preference, of course, would be to have three datacenters...if one is 
partitioned off, zookeeper would not respond, which would be perfect. In that 
scenario, our other two would still be up and running in the other two 
datacenters.
Of course I only have two, and I can't host anything externally due to 
corporate security restrictions. It sure would be nice for a smaller-scale 
deployment to just have a simple mirrored option, as opposed to the mandatory 3 
server/quorum requirement. 
I'm investigating a potential third site I can get access to, but I'm just 
trying to fully explore any other potential options.

Thanks for the quick response Ben

-----Original Message-----
From: Benjamin Reed [mailto:[email protected]] 
Sent: Friday, February 03, 2012 4:05 PM
To: [email protected]
Subject: Re: Deployment planning question

what do you want to happen if both datacenters are up, but there is a partition 
so that they cannot communicate with each other? answering that question may 
get you closer to an answer.

i think your two main options are to:

1) designate a data center that you require to be up for things to work. then 
you can put two in that one and one in the other
2) otherwise you need to setup a machine in another datacenter or amazon 
instance or something that will in effect decide which data center can run if 
one of the datacenters goes down or you are in the partition scenario above.

ben

On Fri, Feb 3, 2012 at 1:01 PM, Jason Harmon <[email protected]> wrote:
> We are planning a ZooKeeper deployment, but are struggling with some aspects 
> of our current architecture. We have two data centers; most applications use 
> load balancing between the two data centers to ensure redundancy for disaster 
> recovery etc. ZooKeeper has been challenging for us, because we can't quite 
> figure out how to structure our servers. We aren't starting with lots of 
> clients, so 3 servers should be a good fit initially. However, if we put two 
> servers in one datacenter, and one server in the other, we're setup for a 
> quorum failure if we have a power outage at the datacenter with two boxes.
> Short of setting up a third data center for our division, what options do we 
> have for deploying ZooKeeper effectively, with disaster recovery in mind etc.
> Thanks!
>
> Jason Harmon
> Senior Software Architect
>

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