Can uuid of raid array be changed?

Can uuid of raid array be changed?

[John McMonagle]

Need to duplicate some computers that are using raid 1.

I was thinking of just adding adding an extra drive and then moving it 
to the new system. The only problem is the clones will all have the same 
uuids.  If at some later date the drives got mixed up I could see a 
possibilities for disaster.  Not exactly likely as the computers will be 
in different cities.

Is there a way to change the uuid if a raid array?
Is it really worth worrying about?

John

Re: Can uuid of raid array be changed?

[Luca Berra]

On Sun, Apr 17, 2005 at 05:04:13PM -0500, John McMonagle wrote:
>Need to duplicate some computers that are using raid 1.
>
>I was thinking of just adding adding an extra drive and then moving it 
>to the new system. The only problem is the clones will all have the same 
>uuids.  If at some later date the drives got mixed up I could see a 
>possibilities for disaster.  Not exactly likely as the computers will be 
>in different cities.
>
>Is there a way to change the uuid if a raid array?
>Is it really worth worrying about?
>
you can recreate the array, this will not damage existing data.

L.

-- 
Luca Berra -- bluca@comedia.it
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Re: Can uuid of raid array be changed?

[John McMonagle]

Luca Berra wrote:

> On Sun, Apr 17, 2005 at 05:04:13PM -0500, John McMonagle wrote:
>
>> Need to duplicate some computers that are using raid 1.
>>
>> I was thinking of just adding adding an extra drive and then moving 
>> it to the new system. The only problem is the clones will all have 
>> the same uuids.  If at some later date the drives got mixed up I 
>> could see a possibilities for disaster.  Not exactly likely as the 
>> computers will be in different cities.
>>
>> Is there a way to change the uuid if a raid array?
>> Is it really worth worrying about?
>>
> you can recreate the array, this will not damage existing data.
>
> L.
>
Thanks

I'll try it.
I suspect I'll find out real quick but do you need to a 
--zero-superblock  on all  devices making the raid arrays?

Will this damage the lvm2 superblock info?
Probably a good idea to do a vgcfgback just to be safe..

John

Re: Can uuid of raid array be changed?

[Luca Berra]

On Mon, Apr 18, 2005 at 08:05:22PM -0500, John McMonagle wrote:
>Luca Berra wrote:
>
>>On Sun, Apr 17, 2005 at 05:04:13PM -0500, John McMonagle wrote:
>>
>>>Need to duplicate some computers that are using raid 1.
>>>
>>>I was thinking of just adding adding an extra drive and then moving 
>>>it to the new system. The only problem is the clones will all have 
>>>the same uuids.  If at some later date the drives got mixed up I 
>>>could see a possibilities for disaster.  Not exactly likely as the 
>>>computers will be in different cities.
>>>
>>>Is there a way to change the uuid if a raid array?
>>>Is it really worth worrying about?
>>>
>>you can recreate the array, this will not damage existing data.
>>
>>L.
>>
>Thanks
>
>I'll try it.
>I suspect I'll find out real quick but do you need to a 
>--zero-superblock  on all  devices making the raid arrays?
NO
>Will this damage the lvm2 superblock info?
>Probably a good idea to do a vgcfgback just to be safe..
NO

the idea is after you cloned the drive, create a new array with the
force flag and using as components the cloned disk and the magic word
"missing", this will create a new degraded array and won't touch any
data.
you can then hotadd a new drive to this array, it will fill the slot
used by the "missing" keyword.

L.

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