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From: Jason Harmon <jh033q@att.com>
To: "user@zookeeper.apache.org" <user@zookeeper.apache.org>
Date: Fri, 3 Feb 2012 18:01:03 -0600
Subject: RE: Deployment planning question
Thread-Topic: Deployment planning question
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My preference, of course, would be to have three datacenters...if one is pa=
rtitioned 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 dat=
acenters.
Of course I only have two, and I can't host anything externally due to corp=
orate security restrictions. It sure would be nice for a smaller-scale depl=
oyment to just have a simple mirrored option, as opposed to the mandatory 3=
 server/quorum requirement.=20
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:breed@apache.org]=20
Sent: Friday, February 03, 2012 4:05 PM
To: user@zookeeper.apache.org
Subject: Re: Deployment planning question

what do you want to happen if both datacenters are up, but there is a parti=
tion so that they cannot communicate with each other? answering that questi=
on 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. th=
en 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 in=
stance 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 abov=
e.

ben

On Fri, Feb 3, 2012 at 1:01 PM, Jason Harmon <jh033q@att.com> wrote:
> We are planning a ZooKeeper deployment, but are struggling with some aspe=
cts of our current architecture. We have two data centers; most application=
s use load balancing between the two data centers to ensure redundancy for =
disaster recovery etc. ZooKeeper has been challenging for us, because we ca=
n'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 w=
e put two servers in one datacenter, and one server in the other, we're set=
up for a quorum failure if we have a power outage at the datacenter with tw=
o 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 min=
d etc.
> Thanks!
>
> Jason Harmon
> Senior Software Architect
>