Request for documentation clarification: http://www.couchbase.com/docs/couchbase-manual-1.8/couchbase-introduction-architecture-nodes.html

From a customer:
I see this:

"A cluster is a collection of one ore more instances of Couchbase Server that are configured as a logical cluster. All nodes within the cluster are identical and provide the same functionality and information. Information is shared across the entire cluster.

Clusters operate in a completely horizontal fashion. To increase the size of a cluster, you add another node. There are no parent/child relationships or hierarchical structures involved. This means that Couchbase Server scales linearly, both in terms of increasing the storage capacity and the performance and scalability. "

If my understanding is correct, then I don't understand this part "All nodes within the cluster are identical and provide the same functionality and information". This (to me) implies that each node is the same, and that "providing the same information" would imply that they all contain the same data objects. If this is true, then adding a node would not increase storage capacity (as the last sentence states) but instead would just increase read performance since you now have the same data in more places.

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Here was my response to the customer:
I can see where the confusion is...but actually both parts of this are correct.

By "all nodes within the cluster are identical" means that they each contribute the same amount of resources and functionality to the cluster...there are no "master" nodes, no "head" nodes, etc.

By "provide the same information" we are referring to the REST API (management/monitoring/WebGUI) and the ability for any node to act as a part of a cluster or as a standalone node without any differentiation to the application.