Extending root RHEL physical partition and then the underlying LV

Bit fiddly this so reminder to myself:

• Boot into rescue mode from install DVD
• delete partition with fdisk 
• recreate at same start to end of disk
• reboot
• back into rescue
• Then run these commands

pvresize /dev/sda2 (or 2nd partition on physical disk)
lvextend /dev/mapper/*vg_lv* -l+100%FREE (for all the disk)
resize2fs /dev/mapper/*vg_lv* (to resize FS, may take a short while)

• Check volumes are ok with vgs/lvs
• Reboot to double check everything boots and mounts fine