Multi-tenant architecture

Hi.
We're in the designing proccess of a datawarehouse, the environment has to be multitenant. Most of the approaches point to have a tenant table with the key "on every dimension".

It's really necesary to have every table with a tenant id?
Could it be on the fact tables only?,
If the tenant id is on every dimension table, we are talking about a snowflake schema?, we want to model using star schema.

Another approach is to do a database schema per tenant, but that would imply to have different tables all with the same structure per schema, and what about a structure change? or new requeriment?

We want to have a reports central repository, (the most of the reports could be shared accross all tenant) and then filter by tenant, the user logged would have that attribute.

Hope some one could guide through the right way or share some experience.

Thanks.

I spoke with someone from a multi-tenant company the other day. They said the way to go is a common schema with all data instead of different schemas. I believe they used partitioning to physically separate the data. I wouldn't have thought that was the way to go but apparently keeping all the schemas in sync with the latest changes becomes quite cumbersome. You would want tenant id on all tables because not all reporting hits the fact tables. A pure customer report could run solely off of the customer dimension.

Create one conformed tenant dim and separating tenant with their type, for example Govt, small business etc. If you want to pivot out tenant data then create a tenant type dim and tenant dim and join it in a Fact table.