Date: Fri, 24 Mar 2006 16:22:44 -0800 From: Garrett Cooper <youshi10@u.washington.edu> To: freebsd-questions@freebsd.org Subject: Re: filling up UDP socket buffers like mad Message-ID: <44248D54.80304@u.washington.edu> In-Reply-To: <20060324211741.GA40819@bewilderbeast.blackhelicopters.org> References: <20060324211741.GA40819@bewilderbeast.blackhelicopters.org>
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Michael W. Lucas wrote: >Hi, > >Running FreeBSD 6.1-PRERELEASE as a DNS, dhcp, and syslog server. > >I'm having trouble with DNS, DHCP, and syslogd locking up, and I think >I've found what they all share in common. > >During the lockups, the box starts dropping UDP due to full socket >buffers. I have a dumb little script to capture the rate of drops >over 5 seconds, and it's about 45 a second. > >168725 dropped due to full socket buffers >168958 dropped due to full socket buffers > >Right now, named and syslogd are in cron to restart every 15 minutes. >Once they restart, everything works fine. Immediately after the >reload, the UDP drops cease. The script reveals no change in the >number of drops... for a few minutes. > >I've turned kern.ipc.maxsockbuf to increase the number of UDP buffers, >which Google tells me is correct. Mind you, I'd previously tuned it >to 8388608. I've now doubled that again, to 16777216. I really don't >want to just keep doubling this resource when something happens. > >The best thing to do here is to identify what's using all these >sockets, but I'm stumped on how to do that. My bowels tell me it's >syslogd, because that's the program that is most resistant to >restarting, but that's a pretty crappy reason. Any thoughts? > >Thanks, >==ml > Have you run netstat to determine what the culprit is? Try running netstat -f inet | grep udp | less; this will print out everything with a udp socket to a buffered screen, and maybe you can find out one of the socket file descriptors, then take lsof, for instance, and find out what the program/service is that is causing the issue with your system. -Garrett
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