Date: Fri, 8 Aug 1997 11:24:26 +1000 (EST) From: "Daniel O'Callaghan" <danny@panda.hilink.com.au> To: freebsd-hackers@freebsd.org Subject: Listen queue overflows and SOMAXCONN Message-ID: <Pine.BSF.3.91.970808105311.242C-100000@panda.hilink.com.au>
next in thread | raw e-mail | index | archive | help
I have a Web server which is getting busy and the listen queue is overflowing. Kernel is 2.1.5; binaries are 2.1.7.1. Sysctl reports kern.maxconn=128 Now please don't scream and shout, because I have good reasons for doing what I am doing, but I am running the web servers out of inetd. I want to continue to do so if at all possible. I have rebuilt inetd with listen(...,128) for SOCK_STREAM. inetd runs at about 0.4% CPU according to 'top'. By using the ipfw rule 'allow tcp from any to any 80 in tcpflags syn' I can count the number of syn packets received, and I have been recording number of syns in 10 second periods. It averages 17 and has peaked at 40 between 10am and 11am today. In the same period there were 269 listen queue overflows, for about 4600 actual connections. ~reboot Fri Aug 8 09:04:24 EST 1997 2 listen queue overflows Fri Aug 8 09:25:02 EST 1997 22 listen queue overflows Fri Aug 8 10:00:00 EST 1997 96 listen queue overflows Fri Aug 8 10:17:41 EST 1997 172 listen queue overflows Fri Aug 8 10:59:21 EST 1997 365 listen queue overflows If I have to, I will stop running the servers out of inetd, or build another machine to share the load, but I'm sure FreeBSD should be able to handle this load easily. The machine is a P133 on Gigabyte 512k m/b 48MB RAM, ncr scsi with SCSI-2 disks. top says load average=0.3 and Idle=90% There are 254 IP addresses aliased to lo0. 'netstat -m' says 94 mbufs in use; 29/168 mbufclusters in use. Does anyone have any ideas about what could be the problem, and how to fix it. I have been planning to upgrade the machine to 2.2.2-RELENG - should I plan faster? /* Daniel O'Callaghan */ /* HiLink Internet <http://www.hilink.com.au/>; danny@hilink.com.au */ /* FreeBSD - works hard, plays hard... danny@freebsd.org */
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?Pine.BSF.3.91.970808105311.242C-100000>