I'm running a Windows Server 2003 guest instance in Xen 3.x. This DomU runs fine for a day or two, then stops responding — I don't get any network response, and I can no longer connect to Xen's VNC console for this DomU.

xm list shows this:

Name                                        ID   Mem VCPUs      State   Time(s)
Domain-0                                     0  6508     8     r----- 1161159.4
[A working Linux DomU]                       1   512     1     -b----  68711.1
[The hung Windows DomU]                      5   512     1     ------  67234.2
[Another working Linux DomU]                 3   512     1     -b---- 163036.4

(What does the ------ mean? The xm manual explains what each of the six states mean, but not what no-state means.)

If I xm destroy and then xm create the Windows DomU again, it boots right back up (with the Windows alert The previous system shutdown at [...] was unexpected.), and then stops responding after another day or two.

I checked /var/log/xen/*.log, but no log messages are generated at the time the server stops responding.

How should I proceed in troubleshooting this?