VMware ESX 4.0

So you’ve upgraded your ESX 3.x servers to 4.0 and you’ve upgraded your vCenter server, now you want to access the shiny new hot-add feature to upgrade some running server’s memory. Except you can’t, the feature is no-where to be seen. Something to bear in mind though, your OS needs to support hot-add, so you’ll need a Windows Enterprise or Datacenter edition.

Here’s how to enable it:

Upgrade the VM’s tools, if you haven’t already. This requires a re-boot, but don’t reboot, shut the server down down, otherwise you’ll require another reboot to add the feature. The tools can be upgraded from the system tray icon.