Explanation of Tenant Load Balancer in SaaS maturity model level 4

Question

I\'ve already done some research about SaaS maturity level based on Gianpaolo SaaS maturity model.

Right now I got confused about SaaS maturity level 4. It said, it

Answer 1

One way to implement Tenant Load Balancer:

1. Create multiple instances of the application - say A,B,C. Each with its own database.
2. Create one meta-database - this database has info on accounts, logins, etc.
3. Login interface is single. ie everyone logs on to same web interface.
4. When a user signsup, allocate him to one of the app instances (A,B or C).
5. When user logs in, authenticate against the meta-database and then redirect to specific instance.

So for example:

1. Login site is setup at www.example.com
2. App instances are available at a.example.com, b.example.com, c.example.com
3. To signup, user goes to www.example.com
4. To login, user goes to www.example.com
5. After successful login, user is directed to a.example.com or whatever his instance is.

This is how Salesforce.com does it. They have different instances for different regions and allocate clients these.