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Re: [Xen-users] Is this typical memory usage?

On Wed, 2008-05-21 at 09:15 -0400, Jeff Lane wrote:
> On Tue, May 20, 2008 at 7:43 PM, James Pifer <jep@xxxxxxxxxxxxxxxx> wrote:
> > I'm wondering if I shut down all the domU's and restart if I'll gain
> > some RAM back from dom0? Or, is this typical?
> That sounds about right to me... at least in my experience.  The
> memory ballooning code in Xen is ... strange and does not always
> behave as you may expect it to.  It's also been my experience that
> it's really just best practice to limit dom0 to a small amount of ram
> by default leaving all the rest for guests...
> Typically, I limit dom0 to either 1024 or 2048 MB by using the
> dom0_mem= parameter.  You pass this on the kernel line in grub.  That
> would be the line that actually says kernel and boots the hypervisor,
> NOT the line that says module and boots dom0's kernel.
> I've seen all sorts of fun things with memory ballooning, from memory
> not being recovered (which I think is expected behaviour) to the
> hypervisor refusing to allocate or balloon memory for a new domU.

Okay, so mine has:
    kernel /boot/xen.gz 
    module /boot/vmlinuz- root=/dev/cciss/c0d0p2 vga=0x317 
resume=/dev/cciss/c0d0p1 splash=silent showopts
    module /boot/initrd-

That would become:
    kernel /boot/xen.gz dom0_mem=2048
    module /boot/vmlinuz- root=/dev/cciss/c0d0p2 vga=0x317 
resume=/dev/cciss/c0d0p1 splash=silent showopts
    module /boot/initrd-

Are there any negative side affects with doing this?


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