Resize disk

While working on a VirtualBox VM, I initially gave it 20GB to work with, in a dynamically allocated disk image (VDI). Soon I discovered that I only really had 17GB of space allocated to the root partition and that a large database operation that I wanted to do on this VM used up all available space. So, I needed to increase the disk space allocated to the VM by VirtualBox, and ensure too that the guest OS (Rocky Linux) was aware of the space.

Increasing the size of the disk in VirtualBox 7 was easy enough. With guest stopped, I could access the disk properties in 'Tools' and change the size to 40GB from 20GB. However, it was not sufficient to just restart the VM. Instead, I needed to download a Live CD which I could insert into the virtual CD drive of the guest with the proper tools used to re-partition the guest OS. For this task, I used the Gnome Partition Editor, more commonly known as 'gparted'. gparted-live-1.5.0-6-i686.iso (470MB). The strange part was that even after resizing the guest hard drive, the partitions still were not using the full space available. In the lsblk output below, you can see that sda2 has 39GB available, but that the root volume is only 17GB on disk.

 lsblk -o name,type,fstype,mountpoint,size
NAME        TYPE FSTYPE      MOUNTPOINT  SIZE
sda         disk                          40G
├─sda1      part xfs         /boot         1G
└─sda2      part LVM2_member              39G
  ├─rl-root lvm  xfs         /            17G
  └─rl-swap lvm  swap        [SWAP]        2G
sr0         rom                         1024M

Using df -h, it is clear that the OS thinks it is out of space

[userx@localhost ~]$ df -h
Filesystem           Size  Used Avail Use% Mounted on
devtmpfs             3.8G     0  3.8G   0% /dev
tmpfs                3.8G  540K  3.8G   1% /dev/shm
tmpfs                3.8G  9.3M  3.8G   1% /run
tmpfs                3.8G     0  3.8G   0% /sys/fs/cgroup
/dev/mapper/rl-root   17G   17G   62M 100% /
/dev/sda1           1014M  363M  652M  36% /boot
tmpfs                769M   32K  769M   1% /run/user/1000

The Logical Volume System (LVS) shows

sudo lvs --all
  LV   VG Attr       LSize   Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
  root rl -wi-ao---- <17.00g                                                    
  swap rl -wi-ao----   2.00g 

Taking a look at the Volume Groups, we see that there is one named 'rl' (short for Rocky Linux, and named by our VirtualBox setup when we named the VM 'rl'):

sudo vgs
  VG #PV #LV #SN Attr   VSize   VFree 
  rl   1   2   0 wz--n- <39.00g 20.00g

vgdisplay gives you the most detail as to what is available

# vgdisplay
  --- Volume group ---
  VG Name               rl
  System ID             
  Format                lvm2
  Metadata Areas        1
  Metadata Sequence No  4
  VG Access             read/write
  VG Status             resizable
  MAX LV                0
  Cur LV                2
  Open LV               2
  Max PV                0
  Cur PV                1
  Act PV                1
  VG Size               <39.00 GiB
  PE Size               4.00 MiB
  Total PE              9983
  Alloc PE / Size       4863 / <19.00 GiB
  Free  PE / Size       5120 / 20.00 GiB
  VG UUID               FSoO96-K50l-S1UC-zCLM-y6fz-JRWg-DBKdTP

Test the resize using the --test option

lvextend --test --extents +100%FREE --resizefs /dev/rl/root

Then do it for real without the --test option.

Upon success - which was immediate in my case - I was able to see the newly available space with df and didn't need to do anything further like xfs_growfs

# df -Th
Filesystem          Type      Size  Used Avail Use% Mounted on
devtmpfs            devtmpfs  3.8G     0  3.8G   0% /dev
tmpfs               tmpfs     3.8G  540K  3.8G   1% /dev/shm
tmpfs               tmpfs     3.8G  9.3M  3.8G   1% /run
tmpfs               tmpfs     3.8G     0  3.8G   0% /sys/fs/cgroup
/dev/mapper/rl-root xfs        37G   18G   20G  47% /
/dev/sda1           xfs      1014M  363M  652M  36% /boot
tmpfs               tmpfs     769M   32K  769M   1% /run/user/1000

Reference

1. https://docs.rockylinux.org/books/admin_guide/07-file-systems/
2. https://www.virtualbox.org/manual/ch08.html#vboxmanage-modifymedium (note: I didn't use VBoxManage, I just used the 'Tools' in the VirtualBox GUI)