Quick tip: finding the Azure data center for your Dynamics 365/CRM online environment

Dynamics 365 (CRM) is being hosted in a number of different Azure datacenters - on Administer Power Platform  - Data center regions you will see an overview of the different regions. If your region is EUR (so url is crm4.dynamics.com), then the linked Azure datacenters can be in Amsterdam (West Europe) or Dublin (North Europe). There is a interesting visualization available on Azure Global Infrastructure

If you need to know whether a CRM instance is hosted in Amsterdam or Dublin (for example when you are setting up Azure Synapse Link for Dataverse), you can simply ping the url of your CRM instance (it will time-out but that is no problem) - if the response url starts with ams it is hosted in Amsterdam, if it is hosted in Dublin, the response will start with dub.

If you want to change the primary datacenter from North Europe (Dublin) to West Europe (Amsterdam)  or vice versa, you can open a Microsoft support ticket. This seems to be a quite common operation and the support request is usually treated quite quickly.