[CentOS] Re: raid1 disk format?

Scott Silva wrote:
>>
>>>>
>>>> I'm curious as to why 2 complete dd'd copies don't pair at boot.  
>>>> One comes up running and it does work to mdadm --add the partner 
>>>> partitions and after the resync they do automatically pair at boot.
>>>>
>>> Are they dd copies of the different nodes (IE.. dd copy of sda paired 
>>> with dd copy of sdb)?
>>
>> No - what was sda was dd'd twice with the dups put in sda and sdb.
>>
> That is why it didn't work. The superblock knows which drive it was on, 
> and knows if there are dupes.

But I thought the locations were re-detected at boot/assembly time.

The other question is whether it is possible to change the uuid while 
the system is running or if it would have to be done from a CD boot. 
I've cloned several machines from one initial setup and if copies of the 
disks ever find their way back into one box I'd prefer not to have the 
wrong set try to re-sync.

-- 
   Les Mikesell
    lesmikesell at gmail.com