Expanding OpenLDAP use

Hi,

I'm trying to expanding OpenLDAP use where I work. Right now we use it to handle internal users (about 50000 entries) and organizational data and it work superb. I'm trying to convince my colleagues to also store our customers data but they are worried about the performance since this will be much larger as we have about 4 million customers.

I'm looking for some public uses cases for large number of users in OpenLDAP to give more support to my arguments. So, can anyone share some history or point out some information on the web on that particular subject?

Thanks,

Matheus Morais