Outside a VM, the closest option is Disk cloning – which is best done using a Live-CD (or bootable USB-Stick) to make sure you'll get a consistent clone. There are several Linux distributions specialized on this (don't worry: they don't care what OS is installed on the disks – and you clone the disks, not the OS ;)
- System RescueCD is probably the best known option here. Like almost all of those Live systems, it uses PartImage for disk cloning. And apart from this, it offers a bunch of additional tools, as the name suggests – like TestDisk and PhotoRec to recover lost data.
- Clonezilla also offers a Live system with their cloner on board.
There are several more Live distributions covering this task – but the job is done usually by one of the two cloning solutions mentioned above. And of course, after doing the reverse (restoring the clone), your system is in exactly the state as it was when you created the clone – which can be compared to "restoring a snapshot of a VM". The main difference however is: No "live cloning" – i.e. the system you want to clone must be shut-down, the disks unmounted.