Nagios and threads

[Michal Mertl]

On Wed, 22 Jun 2005, I wrote:
> Daniel Eischen wrote:
> > On Tue, 21 Jun 2005, Michal Mertl wrote:
> > 
> > > Dag-Erling Smrgrav wrote:
> > > > Charles Sprickman <spork at fasttrackmonkey.com> writes:
> > > > > 1. FreeBSD and threads. On FreeBSD there's a native user-level
> > > > > implementation of threads called 'pthread' and there's also an
> > > > > optional ports collection 'linuxthreads' that uses kernel hooks.
> > > >
> > > > This is only the case for FreeBSD 4.  FreeBSD 5 has native threads.
> > >
> > > Yes, the description on Nagios page is not precise but unfortunately
> > > Nagios still has some problems even on 5.4. I wasn't able to find out
> > > what was wrong and the problem dissappeared when I had to replace the
> > > computer with single-processor one. The symptoms I observed were that
> > > every several days one Nagios process was consuming all the CPU doing
> > > hundreds of thousands of syscalls per second. It got always stuck around
> > > the time when the the daily cron job run.
> > >
> > > I did a ktrace on the stuck process and tried to abort it to have the
> > > core but I've lost the ktrace output and it never saved the core :-(.
> > >
> > > I'll install it on another machine and try to diagnose the problem some
> > > more.
> > 
> > You gotta try it on -stable.
> 
> OK. I installed Nagios on a SMP computer with fresh -stable. I tried to
> stress the disk but until now Nagios hasn't hung.
> 
> Michal

Just FYI - I really wasn't able to provoke the hang. I've no idea if the
reason is my upgrade to STABLE or something else. I can only confirm
what went on this thread - Nagios seems to have lots of short lived
children (for the tests) which are probably created with fork and the
main process is multithreaded.

Michal