Re: Reshaping raid0/10

["H. Peter Anvin" <hpa@zytor.com>]

Back in March, Neil Brown wrote:
> 
> Well.... it's not straight forward at all.
> 
> Firstly: it can only work if all your drives are the same size
> (rounded to 64K).  If they aren't raid0 will use all the available
> space on each drive, while raid5 will only use the amount that is
> available on the first drive.
> 
> If that condition is met, then you can safely convert to a raid4 with
> one extra (missing) device by simply creating an array with the same
> drives (so you have to stop and restart the array - you cannot do that
> bit while the array is live).  You seem to need --assume-clean
> to create the raid4 degraded... That is probably a bug in mdadm.
> 

[rest of procedure deleted]

I just wanted to let you know we performed this procedure on
mirrors1.kernel.org.  It was successful, and saved us from copying 3 TB
of data across the Internet.

	-hpa