The Management Server manages one or more zones (typically, datacenters) containing host computers where guest virtual machines will run. The cloud infrastructure is organized as follows:
Zone: Typically, a zone is equivalent to a single datacenter. A zone consists of one or more pods and secondary storage.
Pod: A pod is usually one rack of hardware that includes a layer-2 switch and one or more clusters.
Cluster: A cluster consists of one or more hosts and primary storage.
Host: A single compute node within a cluster. The hosts are where the actual cloud services run in the form of guest virtual machines.
Primary storage is associated with a cluster, and it stores the disk volumes for all the VMs running on hosts in that cluster.
Secondary storage is associated with a zone, and it stores templates, ISO images, and disk volume snapshots.