The need to add an additional hard drive is driven by the guest OS or the VM design requirements. The virtual machine can be in a powered on state while we add the hard disk.
You can add a new virtual hard disk to a VM by editing the settings for the VM.
The following procedure explains how to add a new hard disk to a virtual machine:
Navigate to the VM and Templates inventory view, select and right-click on the VM to which you intend to add a hard disk, and then click on Edit Settings, as shown in the following screenshot:
Use the New device option available in the Edit Settings window, select New Hard Disk as the device option, and then click on Add as indicated in the following screenshot:
Once this is done, a New Hard disk device entry will be added to the Edit Settings window as demonstrated in this screenshot:
Click on the New Hard disk device entry to expand it, and reveal all the advanced settings for that hard drive entry.
Select...