The post describes the renaming of the volume group (vg) being used for the root file system. For example purpose we will be renaming the disk group from vg_old to vg_new.
Steps
1. Rename the Volume Group from vg_old to vg_new :
# vgs VG #PV #LV #SN Attr VSize VFree vg_old 1 2 0 wz--n- 7.88G 0
# vgrename vg_old vg_new Volume group "vg_old" successfully renamed to "vg_new"
# vgs VG #PV #LV #SN Attr VSize VFree vg_new 1 2 0 wz--n- 7.88G 0
2. Replace references to the old VG name ( vg_old ) with the new VG name ( vg_new ) in the files /etc/fstab and /boot/grub/grub.conf. I have changed the 2 references (for swap and root filesystem) with the new disk group name vg_new (highlighted).
# cat /etc/fstab /dev/mapper/vg_new-lv_root / ext4 defaults 1 1 LABEL=/boot /boot ext3 defaults 1 2 tmpfs /dev/shm tmpfs defaults 0 0 devpts /dev/pts devpts gid=5,mode=620 0 0 sysfs /sys sysfs defaults 0 0 proc /proc proc defaults 0 0 /dev/mapper/vg_new-lv_swap swap swap defaults 0 0
Similarly do the changes in /boot/grub/grub.conf :
# cat /boot/grub/grub.conf ... kernel /vmlinuz-2.6.32-642.1.1.el6.x86_64 ro root=/dev/mapper/vg_new-lv_root rd_NO_LUKS LANG=en_US.UTF-8 rd_LVM_LV=vg_new/lv_root rd_NO_MD rd_LVM_LV=vg_new/lv_swap SYSFONT=latarcyrheb-sun16 crashkernel=auto KEYBOARDTYPE=pc KEYTABLE=us rd_NO_DM rhgb quiet ...
3. Create a New Ramdisk Image:
Run the following commands to make a new initial ramdisk image. It is recommended you make a backup copy of the initrd in case the new version has an unexpected problem:
# cp /boot/initramfs-$(uname -r).img /boot/initramfs-$(uname -r).img.bak
Now rebuild the initramfs for the current kernel version:
# dracut -f
4. Reboot the server.
# shutdown -r now