How to increase the size of the disk for existing VirtualBox machine? Use vagrant to create and manage an VirtualBox vm hosting Oracle 12.2.0.1. Please refer to Oracle vagrant box project for more detail. But the original box has two limited disks of size 40G and 16G respectively and mounted one. Even after we increase the size of hard disk in VirtualBox manager, we still can’t see the increased space when log in vm. So we need to create partition on the added space and allocate to logical volume, shown as below.