When you upgrade vCenter Server, you must understand and follow the best practices process for a successful upgrade.

To ensure that each upgrade is successful, follow these best practices:

  1. Make sure that you understand the vCenter Server upgrade process, the effect of that process on your existing deployment, and the preparation required for the upgrade.
  2. Prepare your system for the upgrade.
  3. Back up your vCenter Server databases and SSL certificates
    • Make a full backup of the vCenter Server database and the vCenter Inventory Service database. For the vCenter Server database, see the vendor documentation for your vCenter Server database type. For the Inventory Service database, see the topics "Back Up the Inventory Service Database on Windows" and "Back Up the Inventory Service Database on Linux" in the vSphere Installation and Setup documentation.
    • Back up the SSL certificates that are on the vCenter Server system before you upgrade to vCenter Server 5.5. The default location of the SSL certificates is %allusersprofile%\VMware\VMware VirtualCenter.
  4. Stop the VMware VirtualCenter Server service.
  5. Run the vCenter Host Agent Pre-Upgrade Checker, and resolve any issues. See Run the vCenter Host Agent Pre-Upgrade Checker.
  6. Make sure that no processes are running that conflict with the ports that vCenter Server uses. See Required Ports for vCenter Server.
  7. Upgrade vCenter Server and required components.
  8. Configure new vSphere 5.5 licenses.
  9. Review the topics in After You Upgrade vCenter Server for postupgrade requirements and options.