Bug#440703: mdadm: please add --scan to initramfs local-top script

[Mario 'BitKoenig' Holbe]

On Tue, Sep 04, 2007 at 02:20:13PM +0200, martin f krafft wrote:
> I don't see how this would make a difference. --scan causes mdadm to
> obtain missing information from the configuration file (which should

Well, as long as Debian mdadm doesn't (fully) support non-'standard'
names, it makes less difference.
However, for non-'standard' names, you cannot derive anything from the
name that leads to the right array to assemble (you know virtually
nothing about the array, not even it's minor, given the /dev-entry
doesn't exist). That's why you have to scan the config file for them,
which points you from the name to the uuid, which then points you to the
right array to assemble.

The way for 'standard'-named arrays without --scan is to derive the
minor number from the name, look for superblocks with that preferred
minor and just use them for assembly.

So, even for 'standard'-named arrays --scan does add some stability
given you have - however - arrays with the same preferred minor.

> I appreciate your patch, but I need to first see the problem it's
> trying to fix. Maybe it would help if you pasted a transcript of
> a session *without* the patch.

For non-'standard' named arrays, mdadm just says 'cannot assemble' and
the system stops booting. Hard to get a transcript from it, even with a
serial console, since the initramfs doesn't log userspace output there,
just the kernel does ;)


regards
   Mario
-- 
The question of whether a computer can think is no more interesting than
the question of whether a submarine can swim.          -- E. W. Dijkstra
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