Xen users - Aug 2013 - how to set dom0 memory to fixed size and not to balloon on XCP host

Hi!

I have been tinkering with Ubuntu v. 13.10 and Debian v. 7 Wheezy 64 bit
environments and using Xen as XCP from their package management (resp.
v. 4.2.1 and 4.1.4) and it mostly works all right for my needs. Just one
single host. 

I wonder how i can control how much memory (as seen by free command, or
top) is set for dom0  and i would like to set this as fixed amount, i.e.
no ballooning?

I have tried in grub to set

multiboot       /xen-4.1-amd64.gz placeholder dom0_mem=4G,max:4G

but i suspect since i miss the other part telling not to balloon (where
to do it?), so it doesnt work. The result is that dom0 has aroung 1 G
memory. Interestingly, setting this dom0_mem under 1 G takes effect, say
512 M.

As a side note, using on the same computers XM or XL toolstack and when
i set the dom0_mem similarly and respectively in

# cat /etc/xen/xend-config.sxp
..
(dom0-min-mem 4096)  
(enable-dom0-ballooning no)

or

# cat /etc/xen/xl.conf
..
autoballoon=0

and so there this works. XM and XL dom0 memory size is controllable.


Best regards,

Imre

On Sat, 2013-08-17 at 12:02 +0300, Imre Oolberg wrote:
> I have tried in grub to set
> 
> multiboot       /xen-4.1-amd64.gz placeholder dom0_mem=4G,max:4G
> 
> but i suspect since i miss the other part telling not to balloon (where
> to do it?), so it doesnt work. The result is that dom0 has aroung 1 G
> memory. Interestingly, setting this dom0_mem under 1 G takes effect, say
> 512 M.
Hi Imre,

Question about xapi/XCP/etc are more likely to get answered on the
xen-api@ list.

Ian.