Re: [Xen-users] heavy write crashing, was: process limit

[Tim Freeman <tfreeman@xxxxxxxxxxx>]

On Sat, 14 Jan 2006 03:01:13 +0530
Anand <xen.mails@xxxxxxxxx> wrote:

> On 1/12/06, Tim Freeman <tfreeman@xxxxxxxxxxx> wrote:
> >
> > You can experience some nasty hangs with Xen 3.0.0 when running certain
> > stress
> > invocations in domU, particularly with the --hdd option: "spawn N workers
> > spinning on write()/unlink()" (default is 1GB write()).
> >
> > This is just some casual experience:
> >
> > In a loopback mounted domU, I ran "stress -v --hdd 1" and it will almost
> > immediately kill the machine.
> >
> > I increased dom0's RAM to try and help dom0's kernel with the writing and
> > after
> > giving dom0 a whole gigabyte, it lasted longer but still locks up.
> >
> > I gave dom0 much more CPU (almost half), kept its high RAM allocation, and
> > it
> > did a lot better in this situation, lasted a lot longer, but eventually
> > the
> > system became unresponsive.  Here, console toggling from the keyboard of
> > the
> > real machine still worked up until the time my patience ran out...
> >
> >
> So my guess wasn't wrong after all, a process which tries to do heavy IO
> even with cpu scheduling could cause the entire machine to go down. This
> could be prevented if we could somehow do disk io management between the
> domains.

Yes, the disk I/O scheduling entry on the Xen roadmap is very interesting to us!

http://www.cl.cam.ac.uk/Research/SRG/netos/xen/roadmap.html

It's listed under the "Enhanced QoS features" bullet.  I wonder if "providing
better tools" means an implementation from scratch or a mix of current tools
integrated with Xen?  

Has there been much thinking on any directions this is going to go in?

Thanks! 
Tim 




_______________________________________________
Xen-users mailing list
Xen-users@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-users