Re: Setting up Fakeraid with mdadm
On Thu, Mar 24, 2016 at 11:52:05AM +0100, Christoph Pleger wrote:
> Hello,
>
> I am trying to use an "LSI Megaraid Software RAID" with mdadm, but I have
> not been successful so far. When I configure a RAID 1 in the BIOS
> Setup-Utility and boot from network with an NFSROOT, a ddf container
> device is detected as /dev/md127 and a raid device as /dev/md126, but when
> I reboot, the previously created RAID configuration has been destroyed,
> that is, when I start the BIOS-RAID-Utility again, it does not 'remember'
> the configuration it created earlier.
>
> As a solution of the above problem, I already tried to create an mdadm
> RAID 1 without BIOS support, that is, I deactivated the RAID feature in
> BIOS-Setup and after booting with NFSROOT, used 'mdadm --create ...', but
> I did not manage to make that RAID bootable.
>
> So, how can I setup a RAID 1 over two whole disks with mdadm?
You can either use the LSI's built-in RAID system or mdadm but
not both. Don't use the fakeraid. If you actually have a decent
LSI card (2002 or 3003 chipset) you could use the real RAID that
is provided there, instead. In that case, RAID will show up as
/dev/sda.
Configure the LSI to present individual disks and then use mdadm
the normal way: partition the disks into two sets, a small /boot
partition and a large /. (Or three partitions per disk: /boot, /
and /home.)
Create mdadm pairs for each of sda1,sdb1 sda2,sdb2 sda3,sdb3
... and set /dev/md0, for /boot, as bootable. The Debian
installer can handle all of this easily.
-dsr-
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