Little research how rm -rf and tar kill server

[Mark Felder]

On Mon, Mar 30, 2015, at 11:04, Artem Kuchin wrote:
> 30.03.2015 18:57, Mark Felder пишет:
> >
> > On Mon, Mar 30, 2015, at 10:53, Artem Kuchin wrote:
> >> This is normal state, not under rm -rf
> >> Do you need it during  rm -rf  ?
> >>
> > No, but I wonder if changing the timer from LAPIC to HPET or possibly
> > one of the other timers makes the system more responsive under that
> > load. Would you mind testing that?
> >
> > You can switch the timer like this:
> >
> > sysctl kern.eventtimer.timer=HPET
> >
> > And then run some of your I/O tests
> >
> 
> I see. I will test at night, when load goes down.
> I cannot say sure that's a right  way to dig, but i will test anything :)
> 
> Just to remind: untar overloads the system, but untar + sync every 120s 
> does not.
> That seems very strange to me.  I think the problem might be somewhere
> here.
> 

I just heard from mav that there was a bottleneck in gmirror/graid with
regards to BIO_DELETE requests

https://svnweb.freebsd.org/base?view=revision&revision=280757