[CentOS-virt] Issue with dom0 xen ballooning

[Frederic SOULIER]

Hi all,
I'm having issue with my Centos 5.1 /Xen installation.
I'm having  some  dom0 running 2.6.18-53.1.6.el5xen (x86_64).
On the dom0 where the load is high (more than 70% of total system memory 
consumed by dom0 and domU) we have a  lot of  "memory squeeze ".
The result is that the domU seems to be blocked (no network/no disk 
acces/ etc....).

Looking for a solution in xen user list, it seems the problem come from 
dom0 xen ballooning.
With this option the dom0 attempt to use the maximum of the system 
memory and "balloon" is memory when new domU needs memory.
To resolve it, we have to fix the dom0 memory usage to avoid dom0 
ballooning and crash in our production environnemnt.
The solution seems to pass a parameter at xen boot time (in grub) to 
limit dom0 memory usage : "  dom0_mem=256M "

As anyone encounter this type of problems ?
Is there any other solution than limitting dom0 memory usage ?

Regards

-- 
Frederic Soulier

Administrateur Reseau
Centre de Ressources Informatiques
Université Toulouse 1 Sciences Sociales
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http://cri.univ-tlse1.fr/