I'm pxe booting IBM blades for installation with autoyast. This works, but is very slow due to the absence of a multipath driver in the initrd installation system.

How can I rebuild the initrd used for installation to include dm-multipath, so my initial boot for installation already uses multipathing ?

After installation I can just add 'dm-multipath' to /etc/sysconfig/kernel and run mkinitrd, but the resulting initrd is much smaller than the one provided for installation over pxe on the SLES11 DVD, so I think it will not work for that purpose.

Are the instructions on how to build such a initrd ?