The Centralized EDW

 The centralized EDW approach uses a mainframe model with all data and applications residing on a monolithic platform.

Pro:

Single version of the truth

Con:

• Complex workloads
• Personnel requirements
• Slow-to-adapt technology
• Expensive maintenance
• Expensive upgrades
• High total cost of ownership
• Limited environmental agility

Distributed Independent Data Marts

Pro:

Data marts are highly relevant to the departments using them and the environments are appropriately sized based on need. Departmental ownership is clear.

Con:

• Data silos
• Data duplication
• Impact to operational systems
• Proliferation of technologies
• Data management costs

Hub-and-Spoke Architecture

Hub-and-spoke architectures, sometimes referred to as “federated” EDWs, match the business structure of most large enterprises by offering a centralized EDW and a set of dependent data marts.

Pro:

• The EDW hub allows the enterprise as a whole to set and enforce common standards while enabling analysis and reports that cut across business units.
• The data mart spokes allow business units to meet their own needs quickly at relatively low cost and also conform to the IT requirements of the overall enterprise.
•  A well-managed hub-and-spoke architecture allows business units to set their own budgets and priorities, while contributing as necessary to the central EDW.

Con:

• Difficult to implement
• Unable to distribute the required data quickly enough to meet the needs of the business units

Reference:

http://technet.microsoft.com/en-us/library/dd459147%28SQL.100%29.aspx