The RHEL-6 deployment guide should explain the reserved space capability for kickstart installs. Customers wanting to plan for upgrades to the next major release should be using LVM and reserving space in their volume group so that upgrades will work in the future. The amount of space reserved varies, but should allow for a snapshot to be taken of the root filesystem.
Thank you very much for taking the time to file this bug, David. The Deployment Guide, however, does not describe LVM, nor does it document kickstart installation. The Deployment Guide does mention LVM snapshots, but only as a part of the description of the fs-snapshot plug-in for Yum. And from the errata description, it looks like it would make more sense to document this in the Installation Guide. Please, correct me if I am wrong.
If the Installation Guide is appropriate, that's fine with me. I do not completely understand the difference between the Installation Guide and Deployment Guide. I'll reassign it to Installation Guide.