The section on File Descriptor Requirements (Linux Systems) reminds me of an escalation case I was assigned to in Feburary.
The case involved a global logistics company in Malaysia. It has an issue with Sun Directory Server 5.2 SP4 running on Redhat Enterprise Linux Server AS 4. Long story short - the problem was due to insufficient tuning.
Linux systems limit the number of file descriptors that any one process may open to 1024 per process.
After the directory server has exceeded the file descriptor limit of 1024 per process, any new process and worker threads will be blocked.
For example, if the directory server attempts to open a Oracle Berkeley JE database file when the operating system has exceeded the file descriptor limit, the directory server will no longer be able to open a connection, which results in a corrupted database exception. Likewise, if you have a directory server that exceeds the file descriptor limit set by the operating system, the directory server can become unresponsive as the LDAP connection handler consumes all of the CPU's processing in attempting to open a new connection.
To fix this condition, set the maximum file descriptor limit per process on Linux