In my production env, I’m using Debian 7.6, fog 1.2.0 stock (with a patch to make multicast/scheduled tasks work), in a VM running under ESXi. Single storage node. Crazy reliable and fast. 6.3 GB/Min. Pushes an image out to a lab of 30 computers in ~10 minutes for a 30 G image. Task start to finish including sending Adobe CS 6 Master Collection as a snap in (yes… a snapin), along with several other largeish snapins is about 23 minutes.
Debian 7.6 is pretty much point and shoot for fog 1.2.0. I purging network-manager (debian and ubuntu) (apt-get purge network-manager network-manager-gnome) and statically configuring the network in /etc/network/interfaces as should be done for any server.