Of all the gin joints in all the towns in all the world, Anthony Bourov
had to walk into mine and say:
Hi,
I am running a FreeBSD server, and I am running into this problem very
often. The machine stops responding and instead outputs 1000s of
xl0: no memory for rx list -- packet dropped!
xl0: no memory for rx list -- packet dropped!
xl0: no memory for rx list -- packet dropped!
xl0: no memory for rx list -- packet dropped!
messages. The machine is usually pulling about 4-5 megabits but there is
usually a traffic spike right before this happens so an attack is not out
of the question, but I was wondering if there was any way I can raise the
threshold for this (would more BUFFERs do the trick?).
You don't say what version of FreeBSD this is, or what driver version
you have. Sorry, but my mind reading helmet is in the shop this week.
If you're running something older than 3.2-RELEASE, try the latest
driver from http://www.freebsd.org/~wpaul/3Com. The newer version has
a larger RX and TX ring sizes. If you are running 3.2-RELEASE or later
or changing the ring sizes doesn't help, then try compiling a new
kernel with a larger value for NMBCLUSTERS, i.e.:
options NMBCLUSTERS=2
Actually, for newer versions of FreeBSD, you may have to do:
options NMBCLUSTERS=2
If config(8) complains about the first syntax, try the second. This
will greatly increase the size of the mbuf cluster pool, which should
at least hold off the starvation condition for a while longer. You
might want to check the traffic on the line with tcpdump. I would
look for lots of ICMP or UDP traffic, or maybe lots of TCP segments
directed at ports where there's nothing listening.
Note: each mbuf cluster is 2K in size. 2 * 2048 == 40MB of RAM, so
you better have a lot of memory in this server. If not, try something
smaller.
-Bill
--
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-Bill Paul(212) 854-6020 | System Manager, Master of Unix-Fu
Work: wp...@ctr.columbia.edu | Center for Telecommunications Research
Home: wp...@skynet.ctr.columbia.edu | Columbia University, New York City
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It is not I who am crazy; it is I who am mad! - Ren Hoek, Space Madness
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