# [SOLVED] How to boot on a raid1 software raid ?

## azera

Hello

I am trying to convert my single disk boot to a raid1 boot

So far here is what i have:

- I sucessfully create the raid 1 as degraded with the new drive alone, I copied all the data on it

- I can mount that raid 1, see its files etc

- I already have a raid5 that is working on the same box (although not booting on it)

- I have installed grub on both drive

- When grub boot, it loads the kernel alright, but during the kernel boot it fails to load the "root block device"

The kernel tells me : 

1 - detected that root device is an md device

2 - determining root devices 

3 - mounting root 

4 - mounting /dev/md125 on /newroot failed: input/output error. Please enter another root device: ...

At this point, if I enter /dev/sda3 (my "old" root device that isn't converted to raid yet) everything boots fine without the root. The /dev/md125 device is indeed created but it seems to be created after the error happens, as in it creates it after loading the device, when mdadm is loaded.

Somehow it looks like it can't/doesn't load the raid array before it needs to mount it, and I don't know how I can solve that.

Thanks a lot for any help

My config files (taken from the system once it boots with sda3 as root device):

 *Quote:*   

> $ cat /etc/mdadm.conf
> 
> ARRAY /dev/md/md0-r5 metadata=0.90 UUID=1a118934:c831bdb3:64188b84:66721085
> 
> ARRAY /dev/md125 metadata=0.90 UUID=48ec4190:a80d4dde:64188b84:66721085
> ...

 Last edited by azera on Fri Mar 12, 2010 4:23 pm; edited 1 time in total

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## azera

Problem solved, solution can be found here: http://serverfault.com/questions/121884/linux-boot-on-a-raid1-software-raid

(add mdadm and its configuration to your initramfs)

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