[Gllug] Replacement SATA disk naming

[Nix]

On 5 Mar 2009, Bruce Richardson outgrape:

> On Thu, Mar 05, 2009 at 03:07:09PM +0000, Alain wrote:
>> 
>> I created links sda* -> sdc* .... but the mirroring stuff looks through that
>> to the device numbers:
>> 'mdadm --query --detail /dev/md0' reports:
>
> Are you sure it's tied to the device numbers of the underlying devices?
> I thought it put a superblock into each device which uniqely identifies
> each device in each array.  This should survive a reboot.

This depends on how /etc/mdadm.conf is laid out. If it says (as is
recommended) something like

DEVICE partitions
ARRAY /dev/md0 UUID=3a51b74f:8a759fe7:8520304c:3adbceb1
ARRAY /dev/md1 UUID=a5a6cad4:2c7fdc07:88a409b9:192ed3bf
ARRAY /dev/md2 UUID=fe44916d:a1098576:8007fb81:2ee33b5a
[...]

then it will use the UUIDs of the arrays and devices to assemble
everything in the correct order. If it names underlying block devices
explicitly, you could see it assembling things in the wrong order if
device names change (which would be disastrous).
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