Increase the size of a root partition on a Linux Virtual Machine

1. Extend the virtual disk file size
1. Open a command prompt and navigate to the VirtualBox installation folder.
   
2. List all virtual hard disks and take note of the Location of the disk you want to resize. [code]VBoxManage.exe list hdds[/code]
3. Resize the disk. [code]VBoxManage.exe modifymedium disk "C:\Sudhakar\OracleDBAShop_Blog\VirtualBox VMs\RHEL7.5\RHEL6.5.vdi" --resize 40000[/code]
   
4. Verify disk size. [code]VBoxManage.exe list hdds[/code]
   

Note:To be able to resize a disk it should be created as a dynamically allocated disk. You cannot resize of virtual disk that is created as a fixed size disk.

To convert a fixed disk to dynamic, run
[code]VBoxManage.exe clonemedium disk "C:\Sudhakar\OracleDBAShop_Blog\VirtualBox VMs\RHEL7.5\RHEL6.5.vdi" "C:\Sudhakar\OracleDBAShop_Blog\VirtualBox VMs\RHEL7.5\RHEL6.52.vdi" --variant Standard[/code]

2. Add new Partition

List disk devices and partitions.
[code]fdisk -l[/code]

The above output shows there are two partitions on the disk /dev/sda. To add a new partition, run 

[code]fdisk /dev/sda[/code]

In the fdisk command prompt,

• Enter n to create a new partition.
• Enter p to create primary partition.
• Press ENTER to accept default for first sector.
• Press ENTER to accept default for Last sector. This will create a partition with all the remaining available space on the disk. Alternatively you could specify the size, in my example 4G will add a partition of size 4GB.
• Enter t to set the type of the new partition to Linux LVM.
• Select partition number 3.
• Enter 8e as the Hex code.
• Finally enter the command w to save the changes to disk and exit fdisk.

[code]fdisk -l[/code]

3. Reboot the Virtual Machine and Initialize LVM (Logical Volume Manager)
To initialize LVM on the newly created partition, run
[code]pvcreate /dev/sda3[/code]

4. Add partition to volume group
To do this, first List physical volumes and note the VG Name from the output.
[code]pvdisplay[/code]

Extend the root volume group

[code]vgextend rhel /dev/sda3[/code]

5. Extend the root logical volume.

Identify the path for the root logical volume.

[code]lvdisplay[/code]

Extend the logical volume and resize to filesystem.

[code]lvextend --size +3GB --resizefs /dev/rehel/root[/code]

6. Verify the disk size

To verify the size of root volume, run

[code]df -h[/code]