It’s fairly straightforward to change the hostname using hostnamectl :
Changing the Hostname on Oracle Linux 7
Adding a new disk to Oracle Linux 7 VirtualBox VM using LVM
Add a new disk to the VM in the VirtualBox Manager GUI :
Upgrading Oracle Linux 6 and 7 to UEK4
Oracle recently announced the availabilty of Unbreakable Enterprise Kernel (UEK) Release 4 for Oracle Linux 6 and Oracle Linux 7 Here
Install VirtualBox Guest Additions on Linux
To install VirtualBox guest additions on a RHEL/OEL Linux Guest :
Adding the EPEL yum repository to Oracle Linux 6 and 7
There are some useful utility programs available in the Fedora Extra Packages for Enterprise Linux (EPEL) project, two packages I particularly find useful and always install are htop and rlwrap.