Bug#614353: multipath-tools-boot: upgrade to squeeze breaks machines with root on iscsi

Hanspeter Kunz hkunz at ifi.uzh.ch
Sun Feb 27 10:56:09 UTC 2011

On Sun, 2011-02-27 at 12:02 +0530, Ritesh Raj Sarraf wrote:
> severity 614353 normal
> thanks
> On 02/25/2011 03:26 PM, Hanspeter Kunz wrote:
> > I switched to the /dev/mapper devices for booting as you suggested. that
> > works.
> > 
> > interestingly, after the boot has finished, the /dev/disk/by-uuid
> > symlinks are created correctly. 
> > 
> > Therefore, the only problem is that they are not created during boot.
> > This is clearly a bug. 
> > 
> > I do not know if this is multipath-tools' fault. It could as well be a
> > bug in udev. So please reassign the bug, if necessary.
> > 
> > I would be very thankful if we could resolve this issue as quickly as
> > possible, as I have many machines booting over iscsi, and I would like
> > to migrate them as soon as possible to squeeze (without switching all
> > the device paths in the pxe-config and fstab).
> > 
> > If there is any way in which I can help, please let me know.
> I am confused now of your problem. Initially you mentioned that you have
> multipath involved in your setup. If so, multipath will always add that
> device to its table and not free it, unless you blacklist that
> particular device in multipath's configuration.
> If your requirement is to boot off of the scsi device itself, either
> blacklist the device or purge multipath-tools and rebuild your initrd image.

ok, let me restate the issue, it is actually quite simple:

During boot, after multipath assembled its devices, I see
the /dev/mapper multipath devices (which is fine) but
the /dev/disk/by-uuid symlinks point to one of the underlying iscsi
devices. Therefore, I cannot not boot using root=/dev/disk/by-uuid/...
because this leads to an error (as the device is already used by

when I boot the same system using root=/dev/mapper/... it works. 

after booting, when the system is up, the /dev/disk/by-uuid symlinks
point to the multipath devices (an not anymore to the iscsi devices
directly), which is how it should be.

so the only thing that is missing is that these symlinks are created
correctly during boot.


Hanspeter Kunz                  University of Zurich
Systems Administrator           Department of Informatics
Email: hkunz at ifi.uzh.ch         Binzmühlestrasse 14
Tel: +41.(0)44.63-56714         Office 2.E.07
http://www.ifi.uzh.ch           CH-8050 Zurich, Switzerland

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