When you create a virtual hard disk in VirtualBox, you specify a maximum disk size. If you want more space on your virtual machine’s hard disk later, you’ll have to enlarge the virtual hard disk and partition.

Expand VirtualBox Drive

The first thing you need to do is expand your virtual drive using the VBoxmanage command line tool provided by VirtualBox or the GUI.

Using the GUI:

1. Shutdown the virtual machine that is using the disk.
2. Open the VM VirtualBox Manager (the main window that opens when you launch the GUI)
3. Click File
4. Select Virtual Media Manager from the menu.
5. Select the Hard disks tab.
6. Choose the disk you wish to resize from the list.
7. Click the Properties button.
8. In the Attributes tab, use the slider or text box to specify the new size.
9. Click Apply.

Using the command line:

First, shutdown the virtual machine hat is using the disk.

Replace MB in the examples with how big, in megabytes, you wish to resize the disk to.

Linux/Unix:

$ vboxmanage modifymedium disk /virtual/disk/file --resize MB

Windows:

C:\> cd C:\Program Files\Oracle\VirtualBox
C:\Program Files\Oracle\VirtualBox>VBoxManage modifymedium disk C:\path\to\file --resize MB

If you are running an older version and one of the commands doesn’t work, try this:

vboxmanage modifyhd /path/to/disk --resize MB

Real Example:

$ vboxmanage modifymedium disk \
  "/home/tyler/VirtualBox VMs/CentOS 7 ext4 Clone/CentOS 7 ext4 Clone.vdi" \
  --resize 30000
0%...10%...20%...30%...40%...50%...60%...70%...80%...90%...100%

Resize Partition with GParted

Download the gparted live cd.

Attach the gparted live cd as a drive to your virtual machine and make it the “Primary Master”.

Note: Ensure the checkbox “Live CD” is selected when you add the CD drive.

Now start your VM.

The gparted UI will load. Now resize the parition by expanding it to use the available free space on the virtual disk.

Shutdown your VM, remove the gparted live cd drive and set your virtual disk to once again be the “Primary Master” drive.

However, after you restart your VM you will notice that CentOS is still not aware of the additional space:

df -h

Expand CentOS Partition

Now you will need to expand your Linux partition to use the free space on the drive.

First check the sizes of the current partitions and get the name:

vgdisplay -v

On my system the name of the partition to expand was “/dev/centos/root”.

Extend the volume with the available free space:

lvextend -l +100%FREE /dev/centos/root

Now you are ready to perform the online resize:

xfs_growfs /dev/centos/root

NOTE: resize2fs works on other distributions of Linux but not on CentoOS, so you must use xfs_growfs.