On Mon, Oct 5, 2009 at 10:16 AM, Chris <cjd...@brokensolstice.com> wrote:
> I just reinstalled 4.5.  I touched nothing on the system.  I installed
> mutt through pkg_add, then created a 1M empty file from /dev/null.
>
> I sent this email to myself thusly: mutt -a 1megfile m...@myaddress.com
> </dev/null
>
> Same exact behavior.  It spools, then I have about .5 - 1 second
> before then entire system locks up.

Random guess: sendmail is one of the few standard programs that makes
heavy use of fsync().  Perhaps there's something on the "deal with
stuff being forced to 'disk'" paths of the xen emulation that confuses
the kernel.  If so, the turning off sendmail's SuperSafe option in the
sendmail.cf should make things more stable.  That would be *JUST* a
debugging measure, as doing that on a production server, particularly
one which is unstable, is a recipe for losing email.

The other question is whether you've tried breaking into ddb from the
console when this happens.  Make sure you have ddb.console=1 in your
/etc/sysctl.conf and read the ddb(4) manpage.  (If xen doesn't offer
console access then throw it out.)


Philip Guenther

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