Virtual Box: how to grow a virtual disk
Surprisingly, this isn't available in the disk settings for the VM.
Instead from the main menu
Files > Tools > Virtual Media Manager
From there its pretty obvious what to do.
Next, you need to grow the guest filesystems.
You can boot the Gparted bootable iso in Virtual Box.
(Your gparted .iso)
(Your guest disk image - might be .vdi)
Or, use commands while in the guest OS.
On Fedora I successfully did:
print all Lists all partitions and I see I want 2 larger
resizepart 2 100%