Re: How does one assemble a DDF or IMSM array?

[Wakko Warner <wakko@animx.eu.org>]

Albert Pauw wrote:
> you can start them by using "mdadm -As", that will start up the
> container first and the other md devices after.
> This will work without mdadm.conf, but it is always good to create a
> proper mdadm.conf (mdadm -Es > /etc/mdadm.conf).
> 
> As for what it is, the container contains the disks (in your case
> sda and sdb), the disks are not the container.
> 
> So you create a container first:
> mdadm -CR /dev/md127 -e ddf -l container -n 2 /dev/sda /dev/sdb
> Create a RAID1 device of 1 GB in there
> mdadm -CR /dev/md0 -l 1 -n 2 /dev/md127 -z  1G
> Create another RAID1 device of 50 MB in there
> mdadm -CR /dev/md1 -l 1 -n 2 /dev/md127 -z 50M
> 
> (in this case both md devices are created on the same two disks).
> 
> If you have e.g. 5 disks you can create two separate RAID1 and RAID5
> devices in the container:
> 
> mdadm -CR /dev/md127 -e ddf -l container -n 2 /dev/sda /dev/sdb
> /dev/sdc /dev/sdd /dev/sde
> mdadm -CR /dev/md0 -l 1 -n 2 /dev/md127
> mdadm -CR /dev/md1 -l 5 -n 3 /dev/md127
> 
> Now, two disk are used fully for the RAID 1 device and three fully
> for the RAID 5 devices, they both have their own set of disks.

I created 2 ddf disks in a container on /dev/sd[ab].  I had 3 MD devices at
that time.

> Stopping them all:
> mdadm -Ss
> 
> Starting them all:
> mdadm -As

This did stop the devices, but would not start them back up.  mdadm 3.2.5
was used.

In your example, suppose I have md0 in use and md1 was not in use and was
stopped.  How would I get md1 started back up w/o shuttind down md0 and
md127?

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