Re: Debian/raid1/mdadm/devices not created at boot time

Samuel Tardieu schrieb:

Hi.

I have migrated my Debian -unstable system to raid1 handled by madm as
directed in http://xtronics.com/reference/SATA-RAID-debian-for%202.6.html.
I use Linux 2.6.9, / is on md2, /boot on md0 and swap on md1. I use
mdadm 1.7.0 (the one shipped with Debian).

At boot time, the kernel correctly boots from md2 but init fails to
mount md0 as /boot and setup the swap space on md1 as those devices do
not exist.

If I create them by hand with "cd /dev && ./MAKEDEV md" when I get a
root shell for maintenance and start them using "mdadm -A -s", I can
continue the boot process manually.

The partition types are set to 0xfd, /proc/mdstat reports:
Personalities : [raid1] md0 : active raid1 sda1[0] sdb1[1]
      192640 blocks [2/2] [UU]
      
md1 : active raid1 sda5[0] sdb5[1]
      1951744 blocks [2/2] [UU]
      
md2 : active raid1 sda6[0] sdb6[1]
      37110016 blocks [2/2] [UU]
      
unused devices: <none>

As far as I can tell, the "mdadm-raid" script which does "mdadm -A -s"
is present as /etc/rcS.d/S25mdadm-raid which is a right place as it
will be run before mounting other file systems. However, the absence
of /dev/md0 and /dev/md1 prevent the raid arrays from being started.

What can I do to ensure that /dev/md0 and /dev/md1 exist when the
script is run?

  Sam

Hi!

I just overflew the link you gave. There the partition type "fd"
approach is used, which needs either compiled-in raid functionality or
raid as a module in the initial ramdisk (which is both at least fo Woody
not the standard case; I built a bootable cd with a kernel with
compiled-in raid support so that I could install directly onto a raid).

If you want the disks to be started by the mdadm call in that script,
then the devices shouldn´t be assembled (or even tried to) by
autodetection before. Try changing the type back to 83/82 or whatever fs
you use.

What exactly does lead you to the thought that /dev/md0 and /dev/md1 do
not exist? Are the actual entries in /dev issing? If so, why are they
missing again after you made them wit MAKEDEV?

Norman.

-- 
Norman Schmidt          Institut fuer Physikal. u. Theoret. Chemie
Dipl.-Chem. Univ.       Friedrich-Alexander-Universitaet
schmidt@naa.net         Erlangen-Nuernberg
                        IT-Systembetreuer Physikalische Chemie

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