Hi,
We use GRML as rescue system on our machines. The /boot partition (which sits on a software raid1) of the main system includes the GRML-Kernel, initrd and squashfs so in case someone unintentionally removes libc6 or does some other bad things it's possible to recover the machine via the grml boot option in grub.
the good thing is that this works if the /boot partition is on ide devices because the ide drivers are compiled into the kernel and the raid code in the kernel autostarts the raid.
the bad thing: it doesn't work with our new dell boxes with mpt fusion controllers. the second problem here is that these boxes don't have ps/2 keyboard connectors and grml doesn't recognise the usb keyboard when it puts me into the rescue shell ... argh.
here is what i did to fix these problems:
- when grml loads the usb kernel modules it also tries to insmod usbhid.ko but this one has unknown symbols because ff-memless.ko has to be loaded first. so i copied ff-memless.ko to the initrd and added it to the list of usb.modules. cool. now i have a keyboard.
- the next thing was that the sysfs-scsi-detection code did not find my fusion mpt controller. after reading /modules/scsi/scsi-modules.txt i knew why: because it was missing from there. after adding the entries for it i ended with a correctly detected controller but without a raid. how is the scsi-modules.txt file created? by hand? maybe it would be better to generate it from /lib/modules/$(uname -r)/modules.{dep,pcimap} because in these files the mpt drivers where referenced ...
- ok so after having the devices i needed to start the raid1 to access the filesystem. unfortunately there is no mdadm in the initrd image of grml so i had to compile a static version of mdadm and put it in /static. after this i added some code to assemble all arrays in case there exists a boot option fromhd=/dev/md*
ok so now everything works. great!
btw: grml is a really cool tool
cheers,