You can easily resize disks when needed. The resize will fail if your current usage is greater than the new size you request. 

To change disk size:

  1. Go to your Control Panel > Cloud > Virtual Servers menu.
  2. Make sure your virtual server is powered off, then click its label to open its details screen.
  3. Click the Storage tab > Disks.
  4. Click the Actions button next to the disk you want to change, then click the Edit link.
  5. Enter a new disk label and size in GB in the fields provided.
  6. Click the Save Disk button.