Bug 2142151

Description of problem:

Documentation for preparing local storage states:
"On Red Hat Virtualization Host (RHVH), local storage should always be defined on a file system that is separate from / (root). Use a separate logical volume or disk, to prevent possible loss of data during upgrades.
"
https://access.redhat.com/documentation/en-us/red_hat_virtualization/4.4/html/administration_guide/chap-storage#sect-Preparing_and_Adding_Local_Storage

In order to ensure a customer can correctly upgrade or reinstall, it should be made clear that the local storage filesystem should be on a separate volume group on a separate physical disk.  The current wording is ambiguous enough that I've seen a customer recently set up system incorrectly and overwrite their storage even though they did follow: 


"Create the local storage on a logical volume:" <--- this part should be explicit that it should be a new volume group or a partition on a disk that is not part of the base RHVH volume group.


Later in our documentation on doing an upgrade we point out to "not select the device(s) storing the virtual machines", which is correct as they should be on a separate device from the base RHVH volume. 

https://access.redhat.com/documentation/en-us/red_hat_virtualization/4.4/html-single/upgrade_guide/index#Upgrading_hypervisor_preserving_local_storage_4-3_local_db
"When selecting the device on which to install RHVH from the Installation Destination screen, do not select the device(s) storing the virtual machines. Only select the device where the operating system should be installed."


We had a customer put 3 disks into one "rhvh" volume, which is how the above documentation could be interpreted. It might be worth changing this part as well:
# mkdir /data
# lvcreate -L $SIZE rhvh -n data
# mkfs.ext4 /dev/mapper/rhvh-data
# echo "/dev/mapper/rhvh-data /data ext4 defaults,discard 1 2" >> /etc/fstab
# mount /data


using 'rhvh' as an example could be confusing as the default install already creates a 'rhvh' volume group, and we want to ensure we do not use that volume group for /data purposes.