yes this is correct. we have sites that do cross data center coordination by basically partitioning the data. the coordination data that pertains to data center 1 will have a set of machines all in data center 1 and perhaps an observer in data center 2, but all changes to that data will be done exclusively in data center 1. then another set of machines is setup in data center 2, with an observer or two in data center 1. if you can partition your coordination data that way, then this setup should work pretty well for you.
ben On Fri, Feb 3, 2012 at 3:52 PM, Ted Dunning <ted.dunn...@gmail.com> wrote: > Another option is to design for partition by putting a ZK in each > datacenter. There are a variety of ways to detect partition so that each > datacenter can function, but also know if there is a partition happening. > It is often true that useful things can be done even in the case of > partition. > > On Fri, Feb 3, 2012 at 2:05 PM, Benjamin Reed <br...@apache.org> wrote: > >> 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 <jh0...@att.com> 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 >> > >>
