LVM: Rename root VG/LV -

LVM: Rename root VG/LV

# Tested on RHEL 6 & 7

# Carry out planned modifications: renaming the existing Volume Group and/or renaming
# the Logical Volume(s). I just wanted to change the name of all LVs belonging to rootvg:

lvs
LV   VG     Attr       LSize   Pool Origin Data% Meta% Move Log Cpy%Sync Convert
home rootvg -wi-ao---- 512.00m
opt rootvg -wi-ao----   1.00g
root rootvg -wi-ao----   1.00g
swap rootvg -wi-ao----   1.00g
tmp rootvg -wi-ao----   1.00g
usr rootvg -wi-ao----   1.00g
var rootvg -wi-ao----   1.00g

lvrename /dev/rootvg/home lv_home
lvrename /dev/rootvg/opt lv_opt
[...]
lvrename /dev/rootvg/usr lv_usr
lvrename /dev/rootvg/var lv_var

# Update /etc/fstab with the new names

vi /etc/fstab

   /dev/mapper/rootvg-lv_root                  /       ext4   defaults   1 1
   /dev/mapper/rootvg-lv_swap                  swap    swap   defaults   0 0
   [...]

# and then...

# RHEL 6 -----------------------------------------------------------------------------------

# Update VG/LV names in /boot/grub/grub.conf

vi /boot/grub/grub.conf
   [...]
   kernel /vmlinuz-2.6.32-358.el6.i686 ro root=/dev/mapper/rootvg-lv_root rd_NO_LUKS [...]

shutdown -r now

# RHEL 7 -----------------------------------------------------------------------------------

# Update VG/LV names in /etc/default/grub

vi /etc/default/grub
   [...]
   GRUB_CMDLINE_LINUX="crashkernel=auto rd.lvm.lv=rootvg/lv_root rd.lvm.lv=rootvg/lv_swap rd.lvm.lv=rootvg/lv_usr rhgb quiet"
   [...]

# Then reboot the system to rescue mode (I used a RHEL 7 rescue cd, option "find Linux
# installation and mount under /mnt/sysimage") and rebuild grub2 using following procedure:

# vgchange -ay rootvg
# mount /dev/sda1 /mnt/sysimage/boot
# mount /dev/rootvg/lv_usr /mnt/sysimage/usr

chroot /mnt/sysimage
grub2-mkconfig -o /boot/grub2/grub2.cfg

exit
shutdown -r now