It should be between 2 - 8 months depending on the complexity and the scale of Ariba project.
Majority of the time we spend for building the environments( e.g. DEV/QA/PRE-PROD/PROD etc) and ensure the connectivity with external system(s).
There are a number of variables that can affect the time this takes:
- Are you simply moving from one machine to another within the same data center, or are you migrating to a brand new data center?
- Are you moving all instances (Development, Test, QA/Staging, Production) or a subset of environments?
- Are you connected to any external systems?
- Will the new environment have different connectivity rules (blocked ports, firewall restrictions, etc.)?
- Are you changing the web server, app server, and DB server at the same time, or just a subset?
These are just a few considerations. If this is a simple move of your Ariba application server configuration/customizations, this could take just a few days (if that). If you're looking at a comprehensive migration (replacing all servers, moving to a new data center, setting up all instances with new hardware, etc.), this could take several weeks or months.
Majid's response sounds like they did a comprehensive migration of all environments.