Re: Implementing --detail-platform for DDF

[NeilBrown <neilb@suse.de>]

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On Wed, 11 Sep 2013 23:00:06 +0200 Martin Wilck <mwilck@arcor.de> wrote:

> Hi Neil,
> 
> I thought I might come up with an implementation of mdadm
> --detail-platform for DDF, but I encountered a problem I'd like to discuss.
> 
> For DDF, we can't scan PCI devices like IMSM does, because we don't know
> all controllers supporting DDF. Thus I considered scanning block devices
> instead and looking at "foreign" vendor strings in the meta data;
> possibly also filtering by device names or types. It occured to me that
> it might be elegant to simply call conf_get_devs() for a list of devices
> to be scanned. But if I do that, config.o and its dependencies must be
> linked with mdmon, blowing up its size considerably. I figure that
> that's a no-go. But I'm also reluctant to write my own DDF-specific
> block device scanning code while there is conf_get_devs() already.
> 
> Perhaps I am misunderstanding the purpose of --detail-platform?
> I wouldn't bother with it if YaST2/libstorage didn't call it in order to
> check if a "fake RAID" platform is present.
> 
> Regards
> Martin

I think it would be wrong for --detail-platform to look at the contents of
disk drives.  If anything, it must look at the 'platform' - the controller.

If YaST2 uses --detail-platform for anything other than IMSM it is doing it
wrong.
I'm currently building a virtual machine running openSUSE 13.1-M4 with DDF
devices.  I'll see what yast thinks of it...

NeilBrown

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