OpenLDAP DB_CONFIG values for a big Server

Hi,

Soon I'll have a x64 Suse machine with 16GB RAM and 4 Intel Cores. We need our OpenLDAP Server to be as fast as possible. I wonder which DB_CONFIG values are suitable for this. Maybe...

set_cachesie 14 0 4 set_lg_regionmax 262144 set_lg_bsize 2097152 set_flags DB_LOG_AUTOREMOVE

...?

Directory will have around 6~8 million entries. I'm not sure if they will be entirely uploaded to the RAM cache, but at least part of will improve speed, I think.

Any help will be appreciated since my experiences with OpenLDAP performance against Sun Directory Server 5.2 has not been good, taking several seconds to answer any ldaprequest :(