Re: Converting RAID5 to RAID0

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

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On Sun Aug 31, 2014 at 12:43:26PM +0000, Mike Muratet wrote:

> I am doing some experiments with mdadm to combine two 1TB disks into a RAID
> array. I used fdisk to create the partitions and mdadm to create a two disk
> RAID5 array. I would like to have more space and I can live without
> redundancy. I searched the man pages and boards for a way to do that and found:
> 
> $ sudo mdadm /dev/md0 -f /dev/sdd
> mdadm: set /dev/sdd faulty in /dev/md0
> $ sudo mdadm /dev/md0 -r /dev/sdd
> mdadm: hot removed /dev/sdd from /dev/md0
> $ sudo echo raid0 > /sys/block/md0/md/level
> 
> -bash: /sys/block/md0/md/level: Permission denied
> 
> which was not the result I expected.
> 
> Is it possible to convert RAID5 to RAID0?
> 
It should be, yes. I'd use "mdadm --grow --level=0" rather than direct
interaction with sysfs though. You may need to add "--force" in order to
get a 1-disk RAID0 array though (it's mentioned as being required for
create anyway).

> There are no data on the disk. Is there a way to start over?
> 
Sure. Just stop the arrays (mdadm -S /dev/md0) and then run a new create
command. You'll be prompted about an existing array (and filesystem, if
you'd created that) but can continue to overwrite with the new settings.

Cheers,
    Robin

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