* The only raid level providing unfettered access to the underlying
filesystem is RAID1 with a superblock at its end, and it has been common
wisdom for years that you need RAID1 boot partition in order to boot
anything at all.
Ah. This shines light on my problem...
The problem is that these three points do not affect any other raid
level (as you can not boot from any of them in a reliable fashion
anyway). I saw a number of voices that backward compatibility must be
preserved. I don't see any need for that because:
* The distro managers will definitely RTM and will adjust their flashy
GUIs to do the right thing by explicitly supplying -e 1.0 for boot devices
The Debian stable distro won't let you create /boot on an LVM RAID1, but
that seems to be the extent of current RAID awareness. Using the GUI, if
you create a large RAID5 and attempt to boot off it -- well, you're
toast, but you don't find out until LILO and grub portion of the
installation fails.
* A clueless user might burn himself by making a single root on a single
raid1 device. But wait - he can burn himself the same way by making the
root a raid5 device and rebooting.
Okay, but:
Why do we sacrifice "the right thing to do"? To eliminate the
possibility of someone shooting himself in the foot by not reading the
manual?
Speaking for clueless users everywhere: I'd love to Read The Fine
Manual, but the Fine md, mdadm, and mdadm.conf Manuals that I've read
don't have information about grub/LILO issues. A hint such as "grub and
LILO can only work from RAID 1 and superblocks greater than 1.0 will
toast your system in any case" is crucial information to have. Not
everyone will catch this particular thread -- they're going to RTFM and
make a mistake *regardless*.
And now, please excuse me while I RTFM to find out if I change the
superblocks to 1.0 from 1.2 on a running array...
--
Moshe Yudkowsky * moshe@xxxxxxxxx * www.pobox.com/~moshe
"If you're not part of the solution, you're part of the process."
-- Mark A. Johnson
-
To unsubscribe from this list: send the line "unsubscribe linux-raid" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
