Architecting a vCloud Director Solution : Operational Considerations : 11.2 VMware vCloud Director Patching : 11.2.1 vCloud Director Cells
   
11.2.1 vCloud Director Cells
vCloud Director cells are patched manually by running executable file. Prior to the upgrade, the cell must be quiesced and put in maintenance mode with the cell management tool. If the update requires a database schema change, the script that updates the database must be performed only on one cell in vCloud Director installation and requires downtime of the entire vCloud Director environment. vCloud Director 8.20 provides an orchestrated upgrade of a multi-cell group which can be triggered from a single place and operation.
Patching a cell operating system can be done non-disruptively by leveraging load balancer and quiescing and shutting down one cell at a time in a group.