Re: deleting mdadm array?

[David Greaves <david@dgreaves.com>]

Janek Kozicki wrote:
> Hello,
> 
> I just created a new array /dev/md1 like this:
> 
> mdadm --create --verbose /dev/md1 --chunk=64 --level=raid5 \
>    --metadata=1.1  --bitmap=internal \
>    --raid-devices=3 /dev/hdc2 /dev/sda2 missing
> 
> 
> But later I changed my mind, and I wanted to use chunk 128. Do I need
> to delete this array somehow first, or can I just create an array
> again (overwriting the current one)?

How much later? This will, of course, destroy any data on the array (!) and
you'll need to mkfs again...


To answer the question though: just run mdadm again to create a new array with
new parameters.


I think the only time you need to 'delete' an array before creating a new one is
if you change the superblock version since it quietly writes different
superblocks to different disk locations you may end up with 2 superblocks on the
disk and then you get confusion :)
(I'm not sure if mdadm is clever about this though...)

Also, if you don't mind me asking: why did you choose version 1.1 for the
metadata/superblock version?

David