[Pkg-xen-devel] Bug#640500: Bug#640500: Bug#640500: xen-hypervisor-4.0-amd64: xend invokes oomkiller and reboots machine when creating DomU's

[Pasi Kärkkäinen]

On Tue, Sep 06, 2011 at 12:54:32AM +0800, Thomas Goirand wrote:
> 
> > That means 8704 MB of memory is used. 
> > 
> > Over the last couple of days, I've experienced that when creating two
> > VM's with 512 MB RAM, the oom-killer is invoked. This should not happen
> > because Dom0 can shrink and because the machine should not restart when
> > it is out of memory.
> > 
> > This is a production Xen host, which is becomming a liability, because
> > it's so unpredictable.
> > 
> > Current Dom0 kernel: Linux arbiter 2.6.32-5-xen-amd64 
> 
> Hi,
> 
> I wouldn't recommend to just let your dom0 shrink. Set it directly to a
> much lower memory footprint, something like 512 MB of RAM, so that the
> Linux kernel sees directly that it doesn't have so much memory to deal
> with, and it will not allocate too big buffers and so on. Here's how to
> do this with the Squeeze grub:
> 
>                 echo "
> # Start dom0 with less RAM
> GRUB_CMDLINE_XEN_DEFAULT=\"dom0_mem=512M\"
> " >>/etc/default/grub
> 
> Then either run update-grub2 or dpkg-reconfigure grub-pc (and of course
> reboot...). If you do that, I'm sure your troubles will go away. You
> shouldn't be running big software in the dom0 anyway. I always done that
> because of habits from running older Xen (since 2.0.7), and because I've
> seen issues with the dom0 ballooning out. To me, ballooning the memory
> of dom0 is more a desktop feature than for a server.
> 
> I believe this bug should be closed, because that's not really an issue
> with Xen (but more with the way the Linux dom0 kernel works). I'll let
> Bastian decide though.
> 
> Thomas Goirand (zigo)
> 

Related link / dom0_mem:
http://wiki.xen.org/xenwiki/XenBestPractices

-- Pasi