Requirements for creating or enlarging an LVM volume

Switch to root user
- ```
sudo -s
```
Install package parted (e.g. under Debian or Ubuntu)
- ```
apt install parted
```
After adding or enlarging a hard disk while VM is running, the SCSI bus must be rescanned
- Scan for new hard disks
  - ```
  for i in /sys/class/scsi_host/*/scan; do echo "- - -">$i; done
```
- Scan for enlarged hard disks
  - ```
  for i in /sys/class/scsi_device/*/device/rescan; do echo 1>$i; done
```
To be able to use the additional hard disk space for LVM, a partition must first be created and initialized as PV (Physical Volume)
- (Optional) Initialization of the partition table with GPT - only for new hard disks (e.g. /dev/sdb)
  - ```
  parted /dev/sdb mktable gpt
```
- Create partition and initialize as PV
  - ```
  parted /dev/sdb unit mib mkpart primary 1 100%
```
- ```
parted /dev/sdb set 1 lvm on
```
  - ```
  partprobe
```
- ```
pvcreate /dev/sdb1
```
- Enlarge an existing partition and its PV (e.g. /dev/sdb1)
  - ```
  parted /dev/sdb resizepart 1 100%
```
- ```
partprobe
```
  - ```
  pvresize /dev/sdb1
```

Create new LVM volume

Create VG (Volume Group) (e.g. "data")
- ```
vgcreate data /dev/sdb1
```
Create LV (Logical Volume) (e.g. "data01")
- ```
lvcreate -l +100%FREE -n data01 data
```
Create file system (e.g. EXT4)
- ```
mkfs.ext4 /dev/data/data01
```
Create mount point (e.g. /data)
- ```
mkdir /data
```

Edit /etc/fstab to automatically mount the LV

Add line:
/dev/data/data01 /data ext4 defaults 0 2

Mount LV
- ```
mount /data
```

Extend an existing volume group with a volume

Add volume to existing volume group
- ```
vgextend data /dev/sdb1
```

Enlarge existing LVM volume

Determine the name of the LV to be enlarged (e.g. /dev/data/data01)
- ```
lvdisplay
```
Enlarge LV
- ```
lvextend -l +100%FREE /dev/data/data01
```

Enlarge file system

```
EXT4: resize2fs -p /dev/data/data01
```

BTRFS: btrfs filesystem resize max /data (/data = Mount point of LV /dev/data/data01)

```
XFS: xfs_growfs /dev/data/data01
```

Important note on enlarging /dev/main/root using additional PVs

The following note only applies to systems that use EFI boot. If the folder /sys/firmware/efi exists, your system uses EFI.

The volume group “main” should not be extended with physical volumes from other hard disks. More precisely, the logical volume “root” in the volume group “main” should not be connected to storage areas located on other hard disks.
If you disregard this, the GRUB boot loader will have problems loading. In the short term, this problem can be solved by explicitly selecting the boot option in the BIOS
- this requires the VMRC -> press “DEL” when starting the VM and select the boot option such as “debian” or “ubuntu