Symas (big commercial backers and developers for OpenLDAP) posted benchmark numbers on their site comparing OpenLDAP with the latest versions of FDS (Fedora DS), OpenDS (the Java based Directory Server from Sun which is still in the early stages of development) and ApacheDS (which does not seem to be able to handle real world loads).

It seems that OpenLDAP outperforms the rest many times over, with FDS having trouble keeping 1 million entries in 8MB of RAM. Good news for OpenLDAP, bad news for FDS (which needs much more work, especially for large scale cases) and it makes me wonder how Sun ONE would perform (since it shares the same code base with FDS).


OpenLDAP vs OpenDS (and ApacheDS)

An older benchmark of OpenLDAP against Sun DS