I need to extend the root (/) partition of a RHEL linux. I know I can do this without too much difficulty by booting in rescue mode. The problem is : the RHEL is a virtual machine running in vSphere ESXi 5.1 environment. I thought I could easily mount a image of the installation cd in the virtual CD/DVD drive and boot in rescue mode from there, but I can't get it to boot from the cd. Can anyone help?