"I have also used the command "apt-clone" to list the currently available boot environments. Basically, using ZFS snapshots the whole machine state is snapshot'ed resulting in a instantly bootable environment. Currently we only have the default environment "rootfs-nmu-000". Now I am going to use apt-clone to "dist-upgrade" the whole system. If this is new to you (who has never seen Ubuntu :) it basically means you're upgrading the whole system to the latest tasty bits...
"Note that the "A" and "C" in the output mean "Active" and "Current". Great, now creating instant bootable system snapshots like that is so useful that it does not relate to software installations only. Say you're running some third party closed source installation application and you're not really sure what's it going to do to your system. Or if the new clueless administrator needs to install something to the server but you think he's probably going to destroy it! In such situations, it's very helpful to manually create a system snapshot. So, let's do just that to create the environment 002 and let's activate it."
