[PATCH} Add RAID devices.

[Andreas Enge]

Hello,

On Fri, Jul 15, 2016 at 10:25:47AM -0400, myglc2 wrote:
> How do you plan to address mdadm and grub config?
> Will you be booting from RAID?

the attached patch adds RAID support to our mapped device mechanism.

To give more explanation:
Like for LUKS devices or file systems, the RAID itself needs to be created
during installation, after booting from the USB key:
   mdadm --create /dev/md0 --level=raid10 --layout=f2 \
      --raid-devices=2 /dev/sda2 /dev/sdb2
   (wait 12 hours or so for 4 TB disks)
   mkfs.ext4 /dev/md0

Then one adds a mapped-device of type raid-device-mapping, adds the
raid10 kernel module to the initrd and can boot from the RAID device.
The mapped-device mechanism calls "mdadm --assemble" and "mdadm --stop".

I might write a more detailed blog post about this; there is a little
subtlety with the non-automatic determination of dependencies between
devices, so one needs to make sure that the partitions to be assembled
are present before the mdadm command is executed.

Looking forward to comments on the patch,

Andreas

0001-system-Add-mapped-devices-for-RAID.patch
Description: Text document