When you upgrade vCenter Server, downtime is required for vCenter Server.

Expect downtime for vCenter Server as follows:

  • The upgrade requires vCenter Server to be out of production for 40-50 minutes, depending on the size of the database. The database schema upgrade takes approximately 10-15 minutes of this time. This estimate does not include host reconnection after the upgrade.

    If Microsoft .NET Framework is not installed on the machine, a reboot is required before starting the vCenter Server installation.

  • VMware Distributed Resource Scheduler does not work while the upgrade is in progress. VMware HA does work during the upgrade.

Downtime is not required for the ESX/ESXi hosts that vCenter Server is managing, or for virtual machines that are running on the hosts.