How much deadlift is too much deadlift?

Too much is

a) when you can't recover in between attempts; and/or

b) when it means you cannot keep great form and injure yourself.

Just because something is "scheduled" for you by the Gods of throwing random *kitten* at a wall and seeing if it sticks, doesn't mean you have to blindly follow it and put yourself in traction.

Use some common sense. Heavy compounds without 100% mental focus and good form are dangerous.