From a ServerFault.com posting SaveTheRbtz:
“I wanted to share knowledge of tuning FreeBSD via sysctls, so i’m posting them with comments. Based on Igor Sysoev (author of nginx) presentation about tuning of FreeBSD to 100,000-200,000 of active connections.”
Direct link: http://serverfault.com/questions/64356/freebsd-configuration-sysctl-tuning