XEN 3 DomU loses network and dies

[Damian Lubosch <dl%xiqit.de@localhost>]

Hello XEN Admins!

Since two days I have huge problems with one DomU machine that loses its 
network connection.
I am runnung NetBSD4 stable with XEN 3.1.2 for DomU and NetBSD3.1 for 
the DomUs. The dom0 itself has only internal network, all internet 
network is routed through a domU router (which runs fine). The 
problematic domU has both, an internal IP (to connect to the other 
DomUs) and an external one for its service. I am using ifconfig alias to 
set up the second IP.

The whole system ran once as XEN 2, in the end of December I updated the 
whole system to XEN 3 and it ran for about 3 weeks. This domU is the 
most active one in my environment. It uses two (system-)file-filesystems 
and one on a real (data-)partition. It has also 466MB of RAM. The MAC 
address is also starting with 00:16:3e. The domU kernel is standard from 
NetBSD3.1

The problem is that only this specific DomU is not reachable by either 
internal nor external network and sometimes I am not even able to login 
through the console over the dom0.

In the dom0 "xm list" show a status of ------ (so no "b" as in the other 
domUs)

As hardware I am using a AMD 3700+ with 1GB Ram and Hardware Raid.

I suspected probably the balloon driver to be the one causing problems. 
Is it possible to completely switch it off? I just found (dom0-min-mem 
0) which will turn off "ballooning" for the dom0 only.
Is netbsd perfectly capable of ballooning?

I hope for some hints/help, since restarting the domU isn't that fun.




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