First to be absolutely clear: Our advice would be, if possible, to go for a Business Central "SaaS" solution in the first place. No doubt about that – is has become a mature platform and the performance overall is good. The customer can omit the cost of the usual hosting partner and always "stay current" with a minimum of effort. Beside that its simply works better with the rest of the Dynamics 365 portfolio than an onPrem. Installation would.
There might be real reasons that prohibits choosing a Business Central in the “true” cloud. Integrations with elder onPrem applications, a very strict company policy’s regarding data security or the company has a large ERP-database. The included capacity is 80 Gb, but you will often need 2 sandbox environments – one for customer testing and one for development. Those sandboxes you need to create will be included in the utilization of the 80 Gb – so 25 Gb might be the real “practical” limit. Of course, you can purchase extra capacity. Some developers might be mentioning docker environments for development but to keep those environments up to date with 3. part applications is a task by itself.
Like any vertical solution a good way to evaluate a given Business Central vertical solution is, how it supports the company value chain. It is also a starting point for us when designing a given functionality within our business scope ("Property Management"). So please keep in mind that functionality needs to fit the purpose at hand, and that should be the same – cloud or no-cloud. It is often worth the effort to conduct a fit/gab analysis to ensure "the fit" of a given solution.
The platform and technical part also need attention because they determine the long-term capabilities of the platform. We are talking about the supplier’s criteria. Or put differently “the technical part” below the surface. That part is harder for a customer to get a hold of. But a customer and/or adviser can apply a few simple rules of thumb in the purchase process of an onPrem solution, so you don’t miss out on some very important points.
First rule: Make sure that the solution you are considering is build purely in Extensions. That is the Software vendor should verify that there are no modifications done in the base application - that is zero footprint in Business Central.
Second rule: The software should also be offered through Microsoft AppSource even if the intend is to use it as an App on the onPrem installation.
Third rule: Make sure that the vendor is committed to distribute an OnPrem. build of the application (an App-file).
Fourth rule: If modifications are planned on top of the solution make sure the vendor has a strategy for automated testing the modifications you make. That means the vendor should have a focus on developing testcases that can be executed automatically.
Fifth rule: Chose a solution partner that has an elaborate strategy for how you stay current even if you are onPrem. The future is SaaS and making the jump as small as possible is in our opinion “best practice” for administrating an onPrem. solution.
The first rule ensures that the upgrading process will be way better that in the old Dynamic NAV days where it could be as costly upgrading a solution as purchasing it originally. You are not home safe yet by obeying this rule alone. Many of the old code constructs are depreciated by Microsoft (as an example the whole.net library is not valid in the cloud). Your solution might not be working in the future, so you need to take more factors into account.
The second rule makes it possible to move your solution into the cloud if you should decide it later on. My bet is that the vendor has overcome the most serious technical obstacles from the past if offering the solution on AppSource. Passing Microsoft’s code validation process is quite harsh, and the critical obsolete code will be removed. Otherwise, the solution would not pass the validation process. The vendor needs to provide an App file so it can be installed onPrem.
The third rule: You depend on getting updates and the updates are distributed through app files. Microsoft pushes updates to the base App and not having access to an updated App.-file can in a worst case situation result in that the solution stops working.
The forth rule is an approach to catch breaking changes at the earliest point in time. This rule is not only important if you are on a cloud platform. If you are not adapting your customization as the base application changes then you are consequently building up technological dept. You will eventually need to pay the dept with ahigh interest!
The fifth rule is also a conclusion. You ought to adhere extensively to cloud principles even if you are planning an onPrem BusinessCentral installation. In the short term it will means additional work, but you will save the cost saved manyfold in the future as you don’t need to invest in a “big bang”.