From mboxrd@z Thu Jan  1 00:00:00 1970
From: Neil Brown <neilb@suse.de>
Date: Thu, 16 Jul 2009 10:56:27 +0000
Subject: Re: RFC: mdadm and bringing up raid sets from initrd (dracut)
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In-Reply-To: message from Dan Williams on Wednesday July 15
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To: Dan Williams <dan.j.williams-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
Cc: David Zeuthen <david-o55+BOBDEFg@public.gmane.org>, Hans de Goede <hdegoede-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>, initramfs <initramfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>, linux-hotplug-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, "Danecki, Jacek" <jacek.danecki-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>, Harald Hoyer <harald-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>, Doug Ledford <dledford-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>

On Wednesday July 15, dan.j.williams@intel.com wrote:
> 
> mdadm-3.0 has facilities to prevent assembly of certain metadata types
> [1] or arrays with certain uuids [2].  I wonder if we also need a
> facility to prevent auto-assembly of arrays *not* listed in
> mdadm.conf?  So the mdadm.conf file installed in the initramfs would
> only identify the root array and all other randomly identified md
> devices would be ignored (rather than assembled with a foreign name).
> 
> Thoughts?

This is exactly the functionality that the 'AUTO' line provides.
Arrays that are listed in mdadm.conf will always be assembled when they
are found.
Arrays that are not listed may or may not be assembled depending on
their metadata type and the setting of 'AUTO'.

So
  AUTO -all

will disable all auto-assemble of arrays that are not listed in
mdadm.conf.

NeilBrown