When you launch a Domino server that runs on Linux, Solaris, or AIX, the following message appears on the console: "WARNING: the maximum number of file handles (ulimit -n) allowed for Domino is 1024. See Release Notes and set the allowable maximum to 20000."
Explains how to increase the maximum number of open files (FD) under Linux operating systems by editing /etc/sysctl.conf and /etc/security/limits.conf file.