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

  • To: "James Pifer" <jep@xxxxxxxxxxxxxxxx>
  • From: "Jeff Lane" <sundowner225@xxxxxxxxx>
  • Date: Wed, 21 May 2008 09:15:05 -0400
  • Cc: Xen List <xen-users@xxxxxxxxxxxxxxxxxxx>
  • Delivery-date: Wed, 21 May 2008 06:15:38 -0700
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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.

------------------> Jeffrey Lane - W4KDH <-------------------
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