James Harper writes:
My original argument in favour of hardware RAID was good BIOS boot support (implying that it still worked seamlessly even in the /dev/sda disk is partly dead case)
You then contested that you could change the BIOS order manually and also that BIOS could also try sda, then sdb, etc.
Changing the BIOS boot order manually is a kludge that you don't have to perform with hardware RAID, and my rant above was addressing the reasons why having the BIOS try sda then sdb etc isn't really solving the problem in some cases.
These issues were why I originally switched from grub to extlinux. While I can think of cases that would still break under extlinux, I haven't run into them. Mostly it was grub's device.map not matching after the BIOS shuffled (or didn't) the disk order to boot sdb. extlinux doesn't *have* a device.map, so it Just Works.