Geo-replication is the replication of data across BookKeeper clusters. In order to enable geo-replication for a group of BookKeeper clusters,
Setting up a global ZooKeeper quorum is a lot like setting up a cluster-specific quorum. The crucial difference is that
Let's say that you want to set up geo-replication across clusters in regions A, B, and C. First, the BookKeeper clusters in each region must have their own local (cluster-specific) ZooKeeper quorum.
BookKeeper clusters use global ZooKeeper only for metadata storage. Traffic from bookies to ZooKeeper should thus be fairly light in general.
The crucial difference between using cluster-specific ZooKeeper and global ZooKeeper is that {% pop bookies %} is that you need to point all bookies to use the global ZooKeeper setup.