Considering GRUB's ability to load from multiple media (flash, HD, tftp)
it would be great to be able to write conditionals into the scripts to
build a boot order like:
try flash first,
if that fails try network,
if that fails try HD
It will be even better if the order can be altered via interaction with
the boot server (DHCP/PXE/TFTP). The grand scheme is to be able to
determine how a machine boots up knowing how the system failed last.
For example, when a system boots up GRUB can inspect some filesystem
flags (whether the ext2 fs on /dev/hda1 was cleanly unmounted, whether
/clean exists on /dev/hda5...) and then interact with the boot server to
determine what kernel and rootfs dev to use.
Of course if the booting process gets wedged after GRUB relinquishes
control there is no coming back to retry other boot options. However
GRUB with this feature allows one to set up a high availability booting
system.
Currently there is the default/fallback mechanism and it actually works
fine for limited purposes. Some simple addition (testing filesystem
flags, if-then-else) to the script will be really nice.
What do you guys think?
