When you upgrade vCenter Server or Platform Services Controller on a virtual machine or physical server running Microsoft Windows, your system must meet specific hardware requirements.

You can upgrade vCenter Server and the Platform Services Controller on the same virtual machine or physical server or on different virtual machines or physical servers. When you upgrade vCenter Server with an embedded Platform Services Controller, you upgrade vCenter Server and the Platform Services Controller on the same virtual machine or physical server. When you upgrade the vCenter Server with an external Platform Services Controller, first install the Platform Services Controller that contains all of the required services on one virtual machine or physical server, and then upgrade vCenter Server and the vCenter Server components on another virtual machine or physical server.

Note: Upgrading vCenter Server on a network drive or USB flash drive is not supported.
Table 1. Minimum Recommended Hardware Requirements for Installing vCenter Server and Platform Services Controller on Windows
Platform Services Controller vCenter Server with an Embedded or External Platform Services Controller for a Tiny Environment (up to 10 Hosts, 100 Virtual Machines) vCenter Server with an Embedded or External Platform Services Controller for a Small Environment (up to 100 Hosts, 1000 Virtual Machines) vCenter Server with an Embedded or External Platform Services Controller for a Medium Environment (up to 400 Hosts, 4,000 Virtual Machines) vCenter Server with an Embedded or External Platform Services Controller for a Large Environment (up to 1,000 Hosts, 10,000 Virtual Machines) vCenter Server with an Embedded or External Platform Services Controller for X-Large Environment (up to 2,000 Hosts, 35,000 Virtual Machines)
Number of CPUs 2 2 4 8 16 24
Memory 4 GB RAM 10 GB RAM 16 GB RAM 24 GB RAM 32 GB RAM 48 GB RAM
Note: If you want to add an ESXi host with more than 512 LUNs and 2,048 paths to the vCenter Server inventory, your vCenter Server instance must be suitable for a large or x-large environment.

For the hardware requirements of your database, see the database documentation. The database requirements are in addition to the vCenter Server requirements if the database and vCenter Server run on the same machine.