I'm working on an application running on Windows servers which requires heavy use of LDAP. For now we are stuck with the slapd LDAP server on a Windows platform - it's not great but for various reasons we are stuck with this architecture.
Our system scales with demand, so at peak times there will be more application servers. Each application server is multi-threaded and may make up to 16 concurrent connections to the single LDAP server.
Any time the system tries to make more than 64 concurrent connections to the LDAP server, the slapd will block any further connection attemps.
It's obvious that the slapd connection pool is maxed-out, but how do I make it bigger? The machine we run Slapd on is a very-powerful 8-core server, so we can theoretically a few hundred concurrent connections. Furthermore, a previous incarnation of this project ran slapd on Ubuntu Linux on a dual-core server. It was able to handle twice the load of ours without any problem, so it would appear that our troubles are Windows spesific.