Cannot access non-LVM /boot partiton.

From: marcus hall
Date: Mon Oct 26 2009 - 23:35:21 EST


Hello..

I have a Fedora system that I recently upgraded to Fedora 11 and subsequently
I cannot access my /boot partition. I have upgraded several systems without
any problems, and I am not sure what to look at that may be the source of
the problem. I've asked on the fedora list with no response, and although I
don't think that it is a kernel problem, perhaps somebody can point me to
the right corner of userspace to start looking deeper.

The problem system has a pair of SATA disks that are mirrored. They each
contain two partitions, a /boot partition on /dev/sda1 and /dev/sdb1, and
an LVM setup on /dev/sda2 and /dev/sdb2. After booting the system, the
only disk device files in /dev are /dev/sda, /dev/sdb, and /dev/sdb2. Grub
sees the boot partition just fine and gets into the kernel, which fails
after userspace starts mounting the filesystems because it cannot find /boot.
If I run fdisk, it is happy with the partition table on either disk.

During boot, the kernel seems to be recognizing the partitions on both disks,
since it shows "sda: sda1 sda2" etc. But, something seems to be disabling
access to the first partition later on. If I manually create a /dev/sda1
or /dev/sdb1 device file, whenever I try to access it I get ENODEV.

When I try to boot an earlier kernel that the system was running happily on
before, I get the same problems, so I believe that this is due to some change
in user space during the "upgrade". It does seem reasonable to block access
to the /dev/sdaX devices, since the mirroring works from the /dev/sdbX
devices, and I am suspecting that something is removing /dev/sdb1 because
it has no LVM data on it, or something. I'm suspecting that this might be
something in udev, but that's a weaker guess.

What could remove access to a disk partition in the kernel after it comes
up? If I cat /proc/partitions, all I see are the LVM partitions.

Thanks in advance!

Marcus Hall
marcus@xxxxxxxxxx
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