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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
[23463.961952] netconsole: interface eth0
[23463.961954] netconsole: remote port 6667
[23463.961956] netconsole: remote IP
[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.


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

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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