Re: What parameters to mdadm, to re-create md device with payload starting at 0x22000 position on backing storage?

[Robin Hill <robin@robinhill.me.uk>]

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On Tue Sep 18, 2012 at 08:53:25AM +0200, Adam Ryczkowski wrote:

> On 2012-09-17 19:49, Robin Hill wrote:
> 
> > Your data offset is 272 sectors, which means you'll need to use an older
> > mdadm version to re-create the array. Newer versions use 2048 sectors,
> > but it looks like version 3.0 uses 272, so grab a copy of that if
> > possible.
> Does it mean, that with the current raid setup I need to stick to the 
> mdadm 3.0, or is there way to convert the arrays to the new layout so I 
> can use a recent mdadm? Re-creating the arrays from scratch would be a 
> very long and complex enterprise.
> 
You only need 3.0 to do the create. Once that's done, you can use any
newer version.

The only way I know of to update the offset location in an existing
array would be to fail the disks one at a time, zeroing the superblocks,
then adding them back into the array using a new mdadm. When it's added
back in, it'll use the new offset location. If you have a spare disk and
a new enough kernel version, you can use the pre-emptive replacement
option, which will prevent the need to run without full parity
available.

Cheers,
    Robin
-- 
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    ( ' }     |       Robin Hill        <robin@robinhill.me.uk> |
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