D365 Retail Cloud: RSSU vs RCSU – Don’t get them confused!

As you might have already heard, in the October 2018 release, Microsoft launched the concept of Retail Cloud Scale Unit (RCSU). One of the reasons this change in infrastructure architecture has been released by Microsoft is in order to increase cloud scalability for customers consuming retail work-loads on the D365 platform. The aim of this blog-post is to explain the role of the Retail Store Scale Unit (RSSU) which was already available in D365 Retail for quite some time and contrast it with the newly released RCSU functionality.

Let’s start with a diagram showing the current (i.e. pre-October 2018 release) D365 Retail cloud infrastructure architecture, while highlighting the position of the RSSU in the architecture.

Essentially the RSSU is an “on-premises” box physically located within the store which allows retailers with intermittent internet (and hence cloud) connectivity issues to still execute cross terminal transactions and shift operations when they lose connectivity to the back office. It contains a retail server, a channel database, CDX Asynch client and the IIS website to enable cloud POS features. Please note that even though the RSSU hardware is running on “on-premises” hardware, this concept is not to be confused with the Microsoft Dynamics 365 for Retail “on-premises” deployment option which is also a recent release from Microsoft. With Cloud deployments and RSSU, your back-office (a.k.a. D365-FinOps and a.k.a. Retail HQ) work-loads are still running in the cloud and when you have connectivity in your store mPOS and (unavoidably) cPOS are still talking to your cloud-hosted deployment back-end. The point is that this partial-“on-premises” setup pre-dates both on-premises support for Retail work-loads and the concept of the RCSU. For RSSU please note the following most important limitation, taken directly from the Microsoft Docs web-site

“In Store Scale Unit, users cannot perform any real time operations such as issuing gift cards, looking up products, or performing credit card transactions, unless there is Internet connectivity to HQ or a payment provider. If the majority of your transactions involve real time transactions, then your Store Scale Unit will always need Internet connectivity to enable the connection to HQ or payment provider.”

Over and above all of the above, mPOS stations also have the ability to be configured to go offline using a local SQL Express database on the POS device itself. Of course, the same limitations for RSSU apply when you are working in offline mode.

RSSU should also not be confused with a hardware state which is another piece of “on-premises” hardware within a retail cloud deployment, the role of which is to allow cloud POS to talk to peripherals (such as cash drawers, pole displays, chit printers etc) which cannot natively interact with cloud POS (unlike keyboards and bar-code scanners which do not need a hardware station).

Now let us switch gears to the RCSU functionality which was part of the October 2018 release. What does this feature get to the table? To answer this you can compare and contrast the following two diagrams (both courtesy of Microsoft and of course based on the demo data-set ).

Essentially, the difference between the first and second diagram above is that the front-office and back-office work-loads have been separated into separate infrastructure which helps improve performance due to better resource governance and load isolation, segregation of work-loads and scalability. It is also has a great advantage when rolling out updates as down-time is significantly reduced as when applying an update, patch or extension not the whole environment goes down but only a specific work-load. Since the back-end and front-end are now separate updates can be applied independently. Back-office does not need to go down when front-office retail work-loads are being upgraded and retail operations can continue if they have RSSU and/or offline functionalities deployed locally in the store, with the same limitations highlighted earlier in this blog post of course including the in-ability to make Real-time service (RTS) calls. Please also note that the functionality will only be available on Production and SAT environments. It is not supported for Tier-1 environments,

Here we see how the world of RCSU, RSSU and offline functionality come together but hopefully not confused with each other. It is important to note that in the current iteration of RCSU you cannot deploy a separate retail scale unit per region. Retail channel regions will maybe provided by Microsoft in one of the future releases.

I believe more exciting times are coming ahead for Microsoft Dynamics 365 for Retail and I am prooud to be part of this journey.

Till next time!