On Monday November 9, dan.j.williams@xxxxxxxxx wrote:
> On Mon, Nov 9, 2009 at 8:43 AM, Jon Nelson
> <jnelson-linux-raid@xxxxxxxxxxx> wrote:
> > I tried to create a raid thusly:
> > mdadm --create /dev/md3 --level=10 --layout=f2 --metadata=ddf
> > --raid-devices=2 --assume-clean /dev/sdc1 missing
> > and while I got a non-zero exit code (1), I did not get an error
> > message or any other indication of failure.
> >
> > The misfeature is that I expected some sort of message.
Thanks for the report. mdadm-3.1.1 will be more verbose.
In that particular case:
mdadm: DDF does not support level 10 arrays
If you try the same with --level=5
mdadm: ddf: Cannot create this array on device /dev/sdc1 - a container is required.
>
> Yes, there should be a message that points out that the external
> metadata formats ('ddf' and 'imsm') require a container to be created
> first and then raid volumes are carved out of that container. The
> mdmon man page has a little blurb on containers. The 'missing' option
> is currently not supported for creating containers so you would need
> to modify this to something like:
I really should do something about supporting the 'missing' option,
and in general being able to specify which devices in the container
should be used....
>
> mdadm --create /dev/md/ddf -e ddf /dev/sdc /dev/sdX -n 2
> mdadm --create /dev/md/volume0 /dev/md/ddf --level=10 --layout=f2
Except that ddf doesn't know "RAID10", it knows "RAID1E" with layouts
of "ADJACENT" (like n2) or OFFSET (like o20).
But mdadm/ddf doesn't handle RAID1E yet - I guess it should.
NeilBrown
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