software raid auto assembly problem on Xen host

Michael Torrie torriem at
Wed Mar 3 15:13:30 MST 2010

Nicholas Leippe wrote:
> You should be able to view all of the superblock metadata with examine
> and/or query management flags to mdadm and see how they are
> configured.

mdadm -E doesn't show anything different after I update the homehost,
unfortunately.  Will play more with this.

>> If I read the manpages correctly, this is how you would change it after
>> the fact (as an example):
>> mdadm -A /dev/md4 --homehost=<vmhostname> --update=homehost --auto=yes
>> /dev/sdd1 /dev/sdp1
>> However this had no effect.  The host still happily assembles
>> everything, even things with this new homehost.  I'm wondering if
>> there's not a bug in the redhat initrd stuff.
> Ah, yes. Forgot about that. Even if you tell the kernel
> raid=noautodetect there may be an init script that looks for md
> devices to assemble. I haven't used redhat recently enough to know.
> You'll have to find it and disable it.

Right.  Since RAID stuff is in a module, the kernel parem doesn't do

> It might be part of the local mount (equivalent) init script.

It's all in the initrd.  I've unpacked it and had a look at the init
script in it.

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