dmraid activation in gentoo kernel
Even gentoo handbook says that good build kernel should work without initrd there are some cases that require it, that’s my case. I’m using build in raid from my motherboard, it contains intel ICH9 chipset, this is no true hardware raid, to work it requires software to be run. I have compiled my kernel with all required switches, but it was not seeing my root partition on raid device, so I have run this command
emerge genkernel; genkernel --dmraid ramdisk
This allowed me to boot my manually compiled kernel to run, just added generated initrd to /boot/grub/menu.lst, not sure if this was needed but I have also added option dodmraid to kernel in the same file.