I'm trying to setup a bootable software RAID that will contain the root filesystem and boot up Linux Mint Qiana. It will be used to run a few graphical monitoring applications in a small datacenter, as well as a simple terminal to access other LAN nodes.
I have two 500GB SATA drives (
/dev/sdb) which I will use to construct the RAID 1 Array. There seems to be many ways to do this, but it's a bit unclear to me how to create a
md0 device that is bootable.
My first approach was to boot using a Live Linux Mint installation CD. I would then switch over to a bash prompt and manually partition
sfdisk. I created a simple partition table which included a single primary partition, along with a swap partition. I then simply cloned the partition table from
sfdisk -d /dev/sda | sfdisk /dev/sdb
Okay, so now I have two drives ready to be assembled into a RAID array. I first create the array by saying:
mdadm --create --verbose --metadata=0.90 /dev/md0 --level=mirror --raid-devices=2 /dev/sda /dev/sdb
About an hour later, the array is finished syncing.
I can now initialize
/dev/md0 by giving it a filesystem:
mke2fs -t ext4 /dev/md0
Okay, so now everything seems good. So, I switch back to the Live CD installation, and install Linux onto
/dev/md0. Everything works until the installer attempts to run
grub-install, after which it receives a fatal error.
So, I've been researching around trying to understand the cause here. I'm not entirely sure why this happens, but my understanding is that it has something to do with the fact that "one does not simply boot from
/dev/md0". It seems that in order to create a bootable multi-device RAID 1 array, you need to either create a separate non-RAID
/boot partition, or use
Unfortunately, I don't exactly understand what this entails. Firstly, I don't want to create a separate non-RAID
/boot partition, because the whole boot of booting from
md0 is for the redundancy. Secondly, my understanding is that the
initramfs approach is necessary to load
mdadm into the rootfs at boot time. But, when I boot from the Live CD and create my RAID array,
mdadm is already loaded into memory, so I don't understand why the installer always gets a fatal error when running
Can someone explain what steps I'm missing here, or provide an outline of how to setup a multi-device mount that can boot?