[dm-devel] zSeries zipl on a blacklisted multipath path.

[Romanowski, John (OFT)]

Hi List,
I run SLES9 on IBM zSeries and I'm trying to hack a way to have my boot
partition on a multipath LUN and yet still be able to run IBM's zipl to
update the boot loader on that LUN.
The SLES9 has kernel 2.6.5-7.276-s390x, device-mapper-1.01.01-1.6,
multipath-tools-0.4.5-0.20.

zipl won't update a multipath boot partition, zipl can't get the
geometry of a device-mapper device and quits with message
"Error: Could not get disk geometry"; this is a device-mapper
limitation, not zipl's fault.
 
Since zipl needs a plain /dev/sdx boot device to update,
my hack idea is to put the boot partition on the multipath LUN and in
multipath.conf blacklist one of the LUN's paths (lets say /dev/sda) so
zipl can use /dev/sda to update the boot loader. I would unmount the
multipath boot partition device from /boot, mount /dev/sda at /boot and
then run zipl.

Any ideas how risky this would be: I/O to the LUN's non-boot partitions
via multipaths and zipl I/O to the LUN's boot partition via the
blacklisted path?
--------------------------------------------------------
This e-mail, including any attachments, may be confidential, privileged or otherwise legally protected. It is intended only for the addressee. If you received this e-mail in error or from someone who was not authorized to send it to you, do not disseminate, copy or otherwise use this e-mail or its attachments.  Please notify the sender immediately by reply e-mail and delete the e-mail from your system.