[Discuss] Grub2 and RAID1 Fedora 20

[me at mattgillen.net (Matthew Gillen)]

On 1/2/2014 1:54 PM, Jerry Feldman wrote:
> sudo grub2-install /dev/sdb
> I assume this would work without damaging anything. (just being paranoid
> to avoid Murphy)

No, it won't damage anything and even if the configuration is slightly
wrong (which it shouldn't be if you have a RAID /boot), at least you'll
have a grub shell when booting off the second disk that you can use to
manually get up and running.  Always a useful thing to do on a secondary
drive even if you're not RAIDing /boot.

I vaguely remember a time when either grub didn't recognize software
raid or there was a bug, and in my grub config I had to boot off
/dev/sda1 instead of the raid-1 device (you can do this because linux
software RAID puts it's metadata at the end of the device, so grub can
read it as a bare ext3 or whatever if you really need to).  Once the
kernel loaded and recognized the RAID devices I presume it did a full
re-sync of the /boot RAID, but it was a small partition (~200MB) and I
only rebooted that machine once every 6 months or so, it didn't worry me
too much.

As Rich said though, grub2 fully supports software RAID devices now
though, so you shouldn't have a problem.

Matt