3.5 vCenter Linked Mode
vCenter linked mode provides a single pane-of-glass to allow a common administrative state to manage multiple vCenter instances. With linked mode configured, users can view and manage the inventories of all participating vCenter Server systems. Tasks invoked on a linked mode object are executed by the vCenter Server that manages the corresponding resource. Linked mode in the vCloud Director context allows viewing of all vCenter Servers that manage vCloud resources.
vCloud Director maximums for powered on virtual machines and registered virtual machines are substantially less than the vCenter linked mode maximums. The number of linked mode objects in a vCloud environment does not reach the linked mode maximums unless multiple vCloud instances are involved.
Additional considerations include the following:

T
he vCenter Server appliance does not support
linked mode.
A vCenter instance can link only with other vCenter instances
of the same
version. Keep this in mind when upgrading all vCenter Server
instances in a vCloud instance.

Upgrading a linked
vCenter instance breaks the link
and the instance becomes independent.