Presentation Layer

Is it typical to have two separate layers in data warehousing environments? One is for ETL layer and the other is for presentation(access to business users) and reporting needs. The data in the two schemas would be the same and want to know if this the best practice that folks implement all the time?

I've never done it that way. ETL has a batch window to update the "warehouse" tables. I do have a test environment that closely mirrors production though.

From a software layer standpoint, yes, it is typical to have ETL and presentation layers.  From a data layer point of view, you typically have a landing/staging area that ETL uses, and a dimensional data warehouse if you are following Kimball's architecture.  The presentation software sits on top of the dimensional warehouse.  So, you have one primary data storage area that is loaded by ETL and accessed by end-users. If you are implementing a store and publish architecture (Inmon, Lindstedt) the data warehouse is separate and distinct from data marts used to support end-user queries. ETL loads the data warehouse (3NF or Data Vault model) and publishes marts (dimensional or otherwise) that users access. In a store and publish architecture, users do not access the data warehouse directly.

Thank you, as always very helpful.