Hill side installation

I am looking at installing a pizza oven into my hillside, where the base will be embedded into the hill. Would there be a problem with the concrete block section buried about 2/3 up the back? I have a design in mind that has 3 courses of block up from the slab, where 2 courses of block are buried in the back, and the slab protrudes from the surrounding hill at around 16" back from the front of the blocks.

If I install standard drainage measures (drain tile and gravel at the base of the blocks atop the slab) will there be any problems with the stability due to the pressure of the surrounding dirt?