Partition erweitern (AlmaLinux/CentOS)

You can do this without rebooting in CentOS 7. Assuming your disk is /dev/vda and standard RHEL/CentOS partitioning:

Extend partition

fdisk /dev/sda

1. Enter p to print your initial partition table.
2. Enter d (delete) followed by 2 to delete the existing partition definition (partition 1 is usually /boot and partition 2 is usually the root partition).
3. Enter n (new) followed by p (primary) followed by 2 to re-create partition number 2 and enter to accept the start block and enter again to accept the end block which is defaulted to the end of the disk.
4. Wollen Sie die Signatur entfernen? Nein
5. Enter t (type) then 2 then 8e to change the new partition type to "Linux LVM".
6. Enter p to print your new partition table and make sure the start block matches what was in the initial partition table printed above.
7. Enter w to write the partition table to disk. You will see an error about Device or resource busy which you can ignore.

Update kernel in-memory partition table

After changing your partition table, run the following command to update the kernel in-memory partition table

partx -u /dev/sda

Resize physical volume Resize the PV to recognize the extra space

pvresize /dev/sda2

Resize LV and filesystem In this command centos is the PV, root is the LV and /dev/vda2 is the partition that was extended. Use pvs and lvs commands to see your physical and logical volume names if you don't know them. The -r option in this command resizes the filesystem appropriately so you don't have to call resize2fs or xfs_growfs separately

df -h

/dev/mapper/almalinux-root   45G     20G   26G   44% /

lvextend -r /dev/mapper/almalinux-root /dev/sda2

https://serverfault.com/questions/861517/centos-7-extend-partition-with-unallocated-space