So most if not all sites running openldap, only use one master server?
Yup, that would be the current state of things. Of course, I've honestly not found this to really be a problem because of the immense stability I've enjoyed since dumping NDS and moving to OpenLDAP. The requirement for multi-master generally comes when there is an underlying stability somewhere in the process. There is of course the corporate 5 9's thing that sometimes requires it as well, on the off chance that something did happen to the master.
--Quanah
-- Quanah Gibson-Mount Principal Software Developer ITSS/Shared Services Stanford University GnuPG Public Key: http://www.stanford.edu/~quanah/pgp.html
"These censorship operations against schools and libraries are stronger than ever in the present religio-political climate. They often focus on fantasy and sf books, which foster that deadly enemy to bigotry and blind faith, the imagination." -- Ursula K. Le Guin