Under the Storage tree ( Figure A) click Controller: SATA and then, near the bottom click the Add Disk button (the green plus sign over the floppy icon), and select Add Hard Disk.
In the Settings window, click the Storage section.
Select it in the VirtualBox main window (left pane) and then click Settings.
(Do not close it by saving the state-it must be powered down.)
Add the actual disk this will be another virtual disk (so you're not actually adding a physical drive for the VM).
SEE: Quick glossary: Virtualization (Tech Pro Research) Adding the disk Let's walk through the steps and, in the end, you'll have added enough storage to keep your virtual server up and working, without fear of running out of space. Thankfully, this task is easy in VirtualBox.
Quick glossary: Storage (TechRepublic Premium).
Subscribe to TechRepublic's Data Center Trends newsletter.
Fed and IBM researchers adding new intelligence to massive storage management system.
Why your company should stop neglecting data storage: 6 tips for getting organized.