vCenter Embedded Linked Mode is enhanced linked mode support for vCenter Server Appliance with an embedded Platform Services Controller.
With vCenter Embedded Linked Mode, you can connect a vCenter Server Appliance with an embedded Platform Services Controller together to form a domain. vCenter Embedded Linked Mode is not supported for Windows vCenter Server installations. vCenter Embedded Linked Mode is supported starting with vSphere 6.5 Update 2 and suitable for most deployments.
Other features of vCenter Embedded Linked Mode include:
No external Platform Services Controller, providing a more simplified domain architecture than an external deployment with enhanced linked mode.
A simplified backup and restore process. See "File-Based Backup and Restore of vCenter Server Appliance" for more information.
A simplified HA process, removing the need for load balancers.
Up to 15 vCenter Server Appliances can be linked together using vCenter Embedded Linked Mode and displayed in a single inventory view.
For a vCenter High Availability (vCenter HA) cluster, three nodes are considered one logical vCenter Server node. See "vCenter Architecture Overview" in vSphere Availability for the vCenter HA architecture overview. A single vCenter Server standard license is needed for one vCenter HA cluster.
Embedded linked mode is not supported for Windows vCenter Server installations.
Embedded Linked Mode with Read Only Replication
If a vCenter High Availability (vCenter HA) instance is connected with another vCenter Server instance with embedded linked mode and vCenter HA failover occurs to the passive node and is unable to communicate with its replication partner on the other vCenter Server node, the replica on the vCenter HA node enters read-only mode.