FreeBSD 6.2-RC2 Available - networking zoneli freeze problem still exist.

[Abdullah Al-Marrie]

On 12/28/06, Thomas Herrlin <junics-fbsdstable at atlantis.maniacs.se> wrote:
> Ken Smith wrote:
>
> <snip>
> > All problems we felt needed to be addressed before 6.2 could be released
> > have been taken care of.
> It still runs networking daemons into a frozen zoneli state on
> heavy/(D)DOS network loads. Such processes cant be kill-9ed so there is
> no way to recover from it. (think frozen sshd and a very remote/headless
> server).
> See the stress test panic called 'Ran out of "128 Bucket"
> <http://people.FreeBSD.org/%7Epho/stress/log/cons210.html>' on the 6.2
> todo list and my own latest test here:
> http://www.maniacs.se/~junics/temp/vmstat-z.txt
> This test was on a new 6.2-RC2 install with no zone limit tweaks nor any
> sbsize limits in /etc/login.conf.
> I just made a vm disk image with replication instructions, however Peter
> Holm have replicated it with his own tools so i have not bothered with
> it until now.
>
> > Unless further testing turns up something new
> > RC2, which is available now for dowloading, will be the last of the
> > Release Candidates and 6.2-RELEASE should be ready in about 2 weeks.
> > Your continued help with testing would be greatly appreciated.  If you
> > notice any problems with RC2 you can submit a PR or send mail to this
> > list.
> >
> <snip>
>
> /Thomas Herrlin

Have you tried these options in kernel?

options DEVICE_POLLING
options HZ=1000

add this line to the end of your /etc/sysctl.conf:

kern.polling.enable=1

DEVICE_POLLING changes the method through which data gets from your
network card to the kernel. Traditionally, each time the network card
needs attention (for example when it receives a packet), it generates
an interrupt request. The request causes a context switch and a call
to an interrupt handler. A context switch is when the CPU and kernel
have to switch from user land (the user's programs or daemons), and
kernel land (dealing with device drivers, hardware, and other
kernel-bound tasks). The last few years have seen significant
improvements in the efficiency of context switching but it is still an
extremely expensive operation. Furthermore, the amount of time the
system can have to spend when dealing with an interrupt can be almost
limitless. It is completely possible for an interrupt to never free
the kernel, leaving your machine unresponsive. Those of us unfortunate
enough to be on the wrong side of certain Denial of Service attacks
will know about this.

More info in here
A guide to server and workstation optimization, by Avleen Vig
http://silverwraith.com/papers/freebsd-tuning.php

-- 
Regards,

-Abdullah Ibn Hamad Al-Marri
Arab Portal
http://www.WeArab.Net/