On Wed, 11 Mar 2015 07:45:54 +0100, Stefan G. Weichinger wrote:

> yesterday I received a shiny new server for a client.
> 
> It brings 4 x 1 TB SATA disks, is capable of UEFI and I started setting
> it up.
> 
> GPT partitioning, small partition(s) for the ESP, some swap, and bigger
> partitions of type fd=raid for creating 2 mdadm-raids (rootfs and data)
> with level 6.
> 
> ok so far.
> 
> Then I spent some hours fiddling with grub2, gummiboot et al to get that
> box booting up fine. dracut doesn't assemble the rootfs-raid etc etc ...
> -> fun

I found this with a LUKS root filesystem, dracut doesn't automatically
detect such devices any more, so speed up the boot. You need to specify
rd.auto or rd.mdraid to force it.

> even if I manage to have it booting via UEFI from /dev/sda1 or so ... I
> still have this single point of failure as the vfat-partitioned ESP is
> on one physical disk only.
> 
> I would like to set it up in a way that it boots even when the /dev/sda
> dies ...

I generally set up boot on a RAID1 across all disks. You can still
access individual disks in a RAID1 array, so you can set your computer
to boot from sda1 then sda2 etc but mount /boot on the array, so all
updates are pushed to all four disks.
 

-- 
Neil Bothwick

I distinctly remember forgetting that.