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I have some problems with stability of Debian guests in my XenServer hosts.

To debug this problem I wanted to use netconsole kernel module, unfortunately, because the Ethernet controller is emulated, it doesn't support polling and in effect netconsole:

[23463.961946] netconsole: local port 6665
[23463.961950] netconsole: local IP 10.10.12.10
[23463.961952] netconsole: interface eth0
[23463.961954] netconsole: remote port 6667
[23463.961956] netconsole: remote IP 10.10.12.1
[23463.961958] netconsole: remote ethernet address ff:ff:ff:ff:ff:ff
[23463.961962] netconsole: eth0 doesn't support polling, aborting.
[23463.961971] netconsole: cleaning up

Are there any alternatives to netconsole not requiring physical access to host? I've got network syslog already configured.

Edit:

How is it possible to log all serial output coming from a particular DomU?

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What happens to your guests? –  Nils Nov 25 '11 at 22:03
    
Disk access hangs with INFO: task jbd2:288 blocked for more than 120 seconds. –  Hubert Kario Nov 26 '11 at 0:42
    
jbd2 is a daemon for syncing the journal block device in ext4. A workaround might be using ext3. –  Nils Nov 26 '11 at 21:26
    
The problem is not limited to jbd2, sometimes it's smbd, sometimes slapd. –  Hubert Kario Nov 28 '11 at 15:27
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3 Answers

This is a bit of stretch, but just got this idea while on my way home and typing this with my iPhone. Yes, I have no life and I must scream. Anyway...

I wonder if pam_tty_audit module could be used for this. Configure a special user for it, make the user automatically login to some tty, gather the reports about screen events afterwards with aureport.

A desperate attempt, I know, but man gotta try.

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Since I did not know what the heck jbd2 is I googled and found this bug (#666828) in the Ubuntu bug database. I was not able to access the associated RedHat bug but this looks like a serious problem that even hits physical machines.

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You may want to run a different domU intended only for serial console to all your other domUs. Then, you can make use of the screen utility to switch from one serial console to a particular domU to another.

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By the way, it is assumed that all domUs are on the same dom0. You also use minicom to serial console to the other domUs. –  bintut Jan 13 '12 at 0:30
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