Microsoft Dynamics AX Master Planning Dilemma: By site or by site/warehouse?

Microsoft Dynamics AX users have a fundamental dilemma when implementing master planning. They typically ask something like the following: "When I have multiple warehouses within one site, should l set up master planning to plan for site and warehouse or just for site?"

This question deserves careful consideration.

For the big picture of modeling inventory locations in AX, Scott Hamilton's article is recommended. Let's start with the basics. Since AX 2009 we have had the construct of site dimension. It was possible to not enable it then, but in AX 2012 and in the new AX this is no longer an option. You will have at least one site. And a site does not function without a warehouse. This means that in your storage dimension groups you will have to activate site and warehouse. Always. Master planning will always run per site. We can't change that either. There is no such thing as "MRP by company". If we remember that "multi-site" can also be called "multi-plant", this becomes very logical. Master planning has to be segregated by site. The big question of this article is whether it should also be segregated by warehouse.

In this storage dimension group screen we see that we cannot uncheck "coverage plan by dimension" for the site.

The AX7 version

Planning by site

Conceptually what we call MRP has ...