The way I set up my earthing system was to pound a 4 foot long piece of 1/2 inch rebar in the ground and then hook up a wire that I ran into the house through a small opening by a window - I hooked a smaller earthing wire to that larger wire. I think driving the ground rod deep enough helps to ensure that you will have good conduction with ground even if you were to have dry weather for a while (the soil stays moist the deeper you go). Two meters seems longer than necessary, but not unreasonable.