RAID1 root - troubles booting in degraded mode

3 messages, 2 authors, 2002-10-30 · open the first message on its own page

RAID1 root - troubles booting in degraded mode

From: Massimiliano Masserelli <hidden>
Date: 2002-10-29 23:07:51

Hi folks! 

I've taken a look at the ML archives, and found an old thread (06/2002) 
on this subject, but found no solution.

I've a working setup with a two disks RAID1 root, which boots
flawlessly. Troubles arise when simulating hw failure. RAID setup is as
follows:

raiddev                 /dev/md0
raid-level              1
nr-raid-disks           2
nr-spare-disks          0
chunk-size              4

device                  /dev/hda1
raid-disk               0

device                  /dev/hdc1
raid-disk               1

If I disconnect /dev/hda before booting, the kernel tries to initialize
the array, can't access /dev/hda1 (no wonder), marks it as faulty, then
refuses to initialize the array, dieing with a kernel panic, unable to
mount root.

If I disconnect /dev/hdc before booting, the array gets started in
degraded mode, and the startup goes on without a glitch.

If I disconnect /dev/hda and move /dev/hdc to its place (so it's now
/dev/hda), the array gets started in degraded mode and the startup goes
on.

Actually, this is already a workable solution (if the first disk dies, I
just "promote" the second to hda and go looking for a replacement of the
broken disk), but I think this is not _elegant_. 8)

Could anyone help me shedding some light on the subject?

Tnx in advance.
-- 
Massimiliano Masserelli
-------------------------------------------------------------------------------
Mayor: "Uh... try to have her home by eleven."
	--Buffy the Vampire Slayer: Enemies

Re: RAID1 root - troubles booting in degraded mode

From: Emilio Gargiulo <hidden>
Date: 2002-10-30 20:18:13

Hi Massimiliano
Have you tryed to set partition id to 0xFD <raid autodetect>, and use a boot 
string as:
root=/dev/md1 ro devfs=mount vga=791
I have the same configuration, and I have a grub bootloader on each raid disk.

Emilio Gargiulo

Alle 00:07, mercoledì 30 ottobre 2002, Massimiliano Masserelli ha scritto:
Hi folks!

I've taken a look at the ML archives, and found an old thread (06/2002)
on this subject, but found no solution.

I've a working setup with a two disks RAID1 root, which boots
flawlessly. Troubles arise when simulating hw failure. RAID setup is as
follows:

raiddev                 /dev/md0
raid-level              1
nr-raid-disks           2
nr-spare-disks          0
chunk-size              4

device                  /dev/hda1
raid-disk               0

device                  /dev/hdc1
raid-disk               1

If I disconnect /dev/hda before booting, the kernel tries to initialize
the array, can't access /dev/hda1 (no wonder), marks it as faulty, then
refuses to initialize the array, dieing with a kernel panic, unable to
mount root.

If I disconnect /dev/hdc before booting, the array gets started in
degraded mode, and the startup goes on without a glitch.

If I disconnect /dev/hda and move /dev/hdc to its place (so it's now
/dev/hda), the array gets started in degraded mode and the startup goes
on.

Actually, this is already a workable solution (if the first disk dies, I
just "promote" the second to hda and go looking for a replacement of the
broken disk), but I think this is not _elegant_. 8)

Could anyone help me shedding some light on the subject?

Tnx in advance.
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Re: RAID1 root - troubles booting in degraded mode

From: Massimiliano Masserelli <hidden>
Date: 2002-10-30 20:18:49

On Wed, Oct 30, 2002 at 09:18:13PM +0100, Emilio Gargiulo wrote:
Have you tryed to set partition id to 0xFD <raid autodetect>, and use
a boot string as: root=/dev/md1 ro devfs=mount vga=791
Yes, I tried, but to no avail. Creating an initrd image with mdadm in
the startup script solved the issue.

Bye.
-- 
Massimiliano Masserelli
-------------------------------------------------------------------------------
L'importante e` di non fare di tutta la merda un fascio.
                -- Altan
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