In order to test Multipath in d-i you still need a patched grub ([http://bugs.debian.org/442382 #442382]).
Multipath Support in Debian Installer:
This needs to be done to support [http://sources.redhat.com/lvm2/wiki/MultipathUsageGuide multipath]ing natively in DebianInstaller:
libaio udeb ([http://bugs.debian.org/440320 #440320]) - done
multipath udeb ([http://bugs.debian.org/440334 #440334]) - done
kernel-wedge needs to support multipath-modules ([http://bugs.debian.org/439410 #439410]) - done
linux-kernel-di-i386 needs to include multipath-modules ([http://bugs.debian.org/440447 #440447]) - done
hw-detect: disk-detect.sh needs to pull in /sbin/multipath and the necessary kernel modules. If there are multipathed devices we need to also pull in partman-multipath. ([http://bugs.debian.org/440439 #440439]) - done
parted: correctly identify multipathed devices ([http://bugs.debian.org/440675 #440675]) - done
partman-base ([http://bugs.debian.org/442236 #442236]) - done:
- needs to skip block devices that are part of a multipathed device (part_of_multipath())
- humandev() needs multipath support
- move all helper functions for the other modules to identify multipath devices here
partman-multipath ([http://git.debian.org/?p=users/joeyh/d-i.git/.git;a=commit;h=5022b5bf4ae6f87279ea4e8f02a7994cd7f8104b added to d-i svn]) - done:
- mark devices as multipath
- call kpartx to create the partition mappings
grub: correctly detect multipath partitions ([http://bugs.debian.org/442382 #442382]) - patch for grub-legacy needs to be updated for grub2
partman-auto: don't skip multipath devices - ([http://bugs.debian.org/468799 #468799]) - done
grub-installer needs the same patch as grub's grub-install and furthermore mustn't treat mpath devices as LVM ([http://bugs.debian.org/468832 #468832]) - done
- update the installer manual (TBD)
put up a [http://honk.sigxcpu.org/projects/multipath-tools/d-i/ netboot image] for easy testing
All the points above do have patches attached, you'll need all the ones that aren't already marked as done to get working multipath support in d-i.
Multipath Testing
To enable multipath support during installation use
install disk-detect/multipath/enable=true
at the installer prompt. If multipathed devices are found these then show up as /dev/mapper/mpathX during installation.
Installing Grub Legacy
Since grub2 doesn't support multipath yet, you have to install a patched grub in the newly installed system. Finish the installation until you're asked to reboot. Then:
- spawn a shell in d-i.
copy the patched grub deb to /target/tmp
- then do:
chroot /target dpkg -i /tmp/grub*deb echo "(hd0) /dev/mapper/mpath0" > /boot/grub/device.map grub --device-map=/boot/grub/device.map
assuming your rootfs is on /dev/mapper/mpath0-part1 enter at the grub prompt:
root (hd0,0) setup (hd0)
- done - you can now reboot