Enlarge a Virtual Disk in VirtualBox VDI

If you have a Virtual Machine and you have created it with fixed size, but in some cases the size you gave it a space less than you need, that's why you have to enlarge it.

The big picture steps:

Enter the path where you have installed your Vbox (Windows in my case)

cd C:\Program Files\Oracle\VirtualBox

Issue this command:

VBoxManage modifyhd "C:\Users\Alejandro\VirtualBox VMs\OL6.6_em12c_db\OL6.6.vdi" --resize 51200

Once you have done that, start your virtual machine (linux in my case)

with root issue this command:

Let's add the space to existing virtual disk

fdisk /dev/sda

- Options n,p,3

"Command (m for help): n
Command action
   e   extended
   p   primary partition (1-4)
p
Partition number (1-4): 3
First cylinder (5608-6527, default 5608):
Using default value 5608
Last cylinder, +cylinders or +size{K,M,G} (5608-6527, default 6527):
Using default value 6527"

Change the partition type to "Linux LVM". In this case, the sequence of entries was, "t, 3, 8e".

8e, its the code of LVM

0  Empty           24  NEC DOS         81  Minix / old Lin bf  Solaris        

 1  FAT12           39  Plan 9          82  Linux swap / So c1  DRDOS/sec (FAT-

 2  XENIX root      3c  PartitionMagic  83  Linux           c4  DRDOS/sec (FAT-

 3  XENIX usr       40  Venix 80286     84  OS/2 hidden C:  c6  DRDOS/sec (FAT-

 4  FAT16 <32M      41  PPC PReP Boot   85  Linux extended  c7  Syrinx         

 5  Extended        42  SFS             86  NTFS volume set da  Non-FS data    

 6  FAT16           4d  QNX4.x          87  NTFS volume set db  CP/M / CTOS / .

 7  HPFS/NTFS       4e  QNX4.x 2nd part 88  Linux plaintext de  Dell Utility   

 8  AIX             4f  QNX4.x 3rd part 8e  Linux LVM       df  BootIt         

 9  AIX bootable    50  OnTrack DM      93  Amoeba          e1  DOS access     

 a  OS/2 Boot Manag 51  OnTrack DM6 Aux 94  Amoeba BBT      e3  DOS R/O        

 b  W95 FAT32       52  CP/M            9f  BSD/OS          e4  SpeedStor      

 c  W95 FAT32 (LBA) 53  OnTrack DM6 Aux a0  IBM Thinkpad hi eb  BeOS fs        

 e  W95 FAT16 (LBA) 54  OnTrackDM6      a5  FreeBSD         ee  GPT            

 f  W95 Ext'd (LBA) 55  EZ-Drive        a6  OpenBSD         ef  EFI (FAT-12/16/

10  OPUS            56  Golden Bow      a7  NeXTSTEP        f0  Linux/PA-RISC b

11  Hidden FAT12    5c  Priam Edisk     a8  Darwin UFS      f1  SpeedStor      

12  Compaq diagnost 61  SpeedStor       a9  NetBSD          f4  SpeedStor      

14  Hidden FAT16 <3 63  GNU HURD or Sys ab  Darwin boot     f2  DOS secondary  

16  Hidden FAT16    64  Novell Netware  af  HFS / HFS+      fb  VMware VMFS    

17  Hidden HPFS/NTF 65  Novell Netware  b7  BSDI fs         fc  VMware VMKCORE 

18  AST SmartSleep  70  DiskSecure Mult b8  BSDI swap       fd  Linux raid auto

1b  Hidden W95 FAT3 75  PC/IX           bb  Boot Wizard hid fe  LANstep        

1c  Hidden W95 FAT3 80  Old Minix       be  Solaris boot    ff  BBT            

1e  Hidden W95 FAT1

Hex code (type L to list codes): 8e

Changed system type of partition 3 to 8e (Linux LVM)

WARNING: Re-reading the partition table failed with error 16: Device or resource busy.

The kernel still uses the old table. The new table will be used at

the next reboot or after you run partprobe(8) or kpartx(8)

Syncing disks.

Write the changes typing w

[root@alexdb ~]# reboot

Add space to LVM partition:

pvcreate /dev/sda3

vgdisplay

vgextend vg_alexdb /dev/sda3

lvdisplay | grep "LV Path"

vgdisplay vg_alexdb| grep Free

lvextend --size +7.04G --resizefs /dev/vg_alexdb/lv_root
or (In come cases you got an error about extend, then use the next sentence)
lvextend --extents +2559 --resizefs  /dev/vg_alexdb/lv_root

df -h (You will get your new space)