Re: Use of iSCSI in domU on Oracle VM 2.1.5

From: Jakub Wartak <>
Date: Tue, 28 Jul 2009 17:26:20 +0200
Message-Id: <>

Dnia niedziela, 26 lipca 2009 19:24, Martin Bach napisaƂ:
> Hi Matt,
> thanks for your quick reply.
> I don't get a kernel oops when performing the "iscsiadm --mode node ...
> --login" operation. /var/log/messages lists the new devices, iscsiadm
> returns success and then the domU reboots. Some research I did suggests
> that the domU can't assign the device name(s) for the new LUNs, the error
> message seems to support this ("register_blkdev: cannot get major 8 for
> sd"). I found a FAQ which suggests turning of the SCSI subsystem in the
> kernel which is not really what I'm keen to do ...
> BTW the domU will never come up again because the iscsi services try to
> reconnect to the same LUN and then die again, but this time with a kernel
> panic (dont't have the output available right now). The only way to
> recover from that is to boot to runlevel 1 and set node.startup to manual
> instead of automatic or disable the iscsi services.
> I'm not 100% sure what you mean by "disable openfiler's export of the disk
> devices" - could you please elaborate a little? I have successfully
> mounted iSCSI LUNs to vmware managed virtual machines using the same setup
> so I assume the openfiler setup is correct (but I'm happy to be proved
> wrong)
> Thank you for your help!


Another idea might be worth checking is that having iscsi services disabled: echo 0 > /proc/sys/kernel/panic_on_oops
then also hardcore it into /etc/sysctl.conf (for further reboots).

It would dump kernel oops into dmesg, from where you could decipher it if the remaining kernel parts still would be operational.

If that doesn't help you could try using "netconsole.ko" module so kernel could ship logging directly via UDP messages from the failure without even touching userspace syslogd (been there, done that, for debugging "/" ext3 oops).

As it was stated I haven't encountered such problems during writing of mentioned article, however please note that I used different versions.

Jakub Wartak
Received on Tue Jul 28 2009 - 10:26:20 CDT

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