Re: [Patch] mdadm ignoring homehost?

[Luca Berra <bluca@comedia.it>]

On Mon, Apr 20, 2009 at 04:08:00PM +1000, Neil Brown wrote:
>On Saturday April 18, dledford@redhat.com wrote:
>> 
>> I've been thinking about this, and this is the method I would suggest.
>> 
>> Add two new keywords to the mdadm.conf file:
>> 
>> ASSEMBLE
>> INCREMENTAL
>> 
>> Allow each of those keywords to have one of three set values:
>> None - Don't attempt to assemble any arrays regardless of whether or  
>> not they are in the mdadm.conf file or not
>> Known - Only assemble arrays with a matching array line
>> All - Attempt to assemble any array found
>> 
>> The combination of the two options and the three settings would allow  
>> you to control mdadm behavior for both array assembly modes  
>> independently.  That, combined with my previous patch, should allow  
>> arrays to assemble well, with known names, allow you to control auto  
>> assembly by udev, and in the event that your machine just exports  
>> volumes to other machines for their use, stop assembly entirely.
>
>Why "None"??  Why would you use "None" rather than "Known" with an
>empty list of arrays?
i believe ASSEMBLE is intended as AUTO ASSEMBLE
so we would have the description for the arry and be able to assemble it
manually using: mdadm -A /dev/md/foo
i would like to be able to define this per array tough

>Why have two options: ASSEMBLE and INCREMENTAL ??
>If what circumstance would you use different settings for these two
>options.
maybe i want to avoid incremental assemble of a big array, which would
result in undesired rebuilds.

>I current have two patches sitting in my scratch queue.  I am by no
>means committed to them.
>
>One allows you to have e.g.
>
>  ARRAY ignore UUID=foo:bar:dead:beef
>
>with the meaning that auto-assembly will ignore that array.  If you
>run
>
>  mdadm --assemble /dev/md/thing --uuid foo:bar:dead:beef
>
>it will still assemble the array, but any auto-assembly will ignore
>it.
it is not clear to me what the difference is from having no line at all


>The other allows you to say:
>
> AUTO -ddf -0.90 +all
>
>which means don't auto-assemble any 'ddf' or '0.90' array, but do
>auto-assemble anything else that is recognised.
>You might want to use dmraid for ddf??
>
>If you just have
>
>  AUTO -all
>

one syntax or the other is ok for me, provided the ability to control
what mdadm is doing.

L.

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