Re: [Patch] mdadm ignoring homehost?

[Luca Berra <bluca@comedia.it>]

On Wed, Apr 22, 2009 at 09:20:49PM -0400, Doug Ledford wrote:
> On Apr 22, 2009, at 12:06 PM, Andrew Burgess wrote:
>> On Tue, 2009-04-21 at 20:15 +0200, Piergiorgio Sartor wrote:
>>
>>> This might be a Fedora 10 issue, so maybe Doug would like
>>> to comment.
>>>
>>> After reboot, someone, I guess udev, tries to automagically
>>> start a RAID, so it assembles /dev/md_d127 with one of the
>>> two components of /dev/md/boot (randomly, it seems).
>>> Later, when /dev/md/boot is assembled, one drive is "busy",
>>> because it belongs to /dev/md_d127, and the array is put
>>> together degraded, i.e. with the other disk only.
>>
>> Just a "me too". I also started seeing this after upgrading to fedora
>> 10. I had to create a startup script to stop md_d0 and reassemble
>> everything else.
>
>
> Yeah, I found the cause for this while working on F11.  The problem is a 
> race condition between udev and a call to mdadm -As in the rc.sysinit.  For 
> F11, I solved this by making udev not process devices using incremental 
> mode if we are still in the rc.sysinit script.  You can change 
> /etc/udev/rules.d/70-mdadm.rules (I think that's the right name, it might 
> be slightly off) to read something like this:
>
> # This file causes block devices with Linux RAID (mdadm) signatures to
> # automatically cause mdadm to be run.
> # See udev(8) for syntax
>
> SUBSYSTEM=="block", ACTION=="add", ENV{ID_FS_TYPE}=="linux_raid_member", \
> 	IMPORT{program}="/sbin/mdadm --examine --export $tempnode", \
> 	RUN+="/bin/bash -c '[ ! -f /dev/.in_sysinit ] && mdadm -I $env{DEVNAME}'"
>
>

i believe i saw this as well, but not at startup, it was when i manually
run mdadm -As, so while your hack to prevent udev from assembling
devices while in sysinit may not be a full solution.

my solution was "rm -f /etc/udev/rules.d/70-mdadm.rules",
works like a charm :P

probably the best solution is preventing concurrent mdadm rules with a
lock.

Regards,
L.




-- 
Luca Berra -- bluca@comedia.it
         Communication Media & Services S.r.l.
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