[arch-general] Why Is My RAID Installing Failing?

[Carlos Williams]

On Mon, Jan 11, 2010 at 1:15 PM, Baho Utot <baho-utot at columbus.rr.com> wrote:
> I always wait cat /proc/mdstat until the raid is finished, even though it says
> you don't have to, I don't want any trouble :)

I see your point but when you have 2x 1 TB drives, you're in for a wait.

>> #mdadm -D --scan >> /etc/mdadm.conf
>
> Don't need this

Hmm. Interesting. The Wiki inidicates this as a crucial point of
getting RAID up and working. Sorry, I am just extremely confused. Also
if I don't do this, the mdadm.conf file has no info on my newly
created RAID1 configuration. How does the system know about it if I
don't add the info? This is really strange to hear this. I am not
doubting your help / advice and obviously what I am doing hasn't
worked to this point so I am open to anything but the mdadm.conf file
is full of commented out data. Are you sure I don't need to run that
command?

>> */etc/rc/conf = I simply add the changes below:
>> - In 'Hardware' section add "MODULES=(md_mod raid)
>
> Don't need that, system already got raid by this stage, if it didn't it could
> read that kernel line or init.

OK - I was told on the mailing list by someone that I 'NEED' this in
order for it (RAID) to work.

>> - HOSTNAME="mypc"
>> - "sshd" added to the "DAEMONS" line
>>
>> */etc/mkinitcpio.conf
>> - add 'mdadm' on the 'HOOKS' line after "sata" & before "filesystems"
>> as noted in the Wiki.
>>
>
> Don't think you need that, that is I don't do that on my system.
> I use grub to "start the array" see below.

Again, the Wiki for Arch emphesizes that this is a crucial section
required for 'Software RAID' to work. Without the HOOKS entry, they
advise RAID will not work.

>> */etc/hosts
>> - Add my FQDN here as follows:
>> 127.0.0.1      mypc.mydomain.tld    mypc
>
> Don't do that do
>
> 127.0.0.1      localhost.localdomain   localhost
> 127.0.0.2      mypc.mydomain.tld    mypc

OK thanks! But I think I can ignore this completely until I get RAID working.

>> #cp -a /etc/mdadm.conf /mnt/etc/mdadm.conf to make sure when the
>> system boots, it is aware of my RAID1 mirror.
>
> Don't need that system already knows about the raid as it has already been
> assembled, by now.  You have marked the partition (FD) as being part of a
> raid array the kernel can handle it.

I just assumed that since /mnt/etc/mdadm.conf has no info about my
RAID, when I reboot my new system, it will then be /etc/mdadm.conf.
Anyways, still confused about this one too.

> Try adding this to grub menu.lst
>
> kernel vmlinuz26 root=/dev/md0 md=2,/dev/sda2,/dev/sdb2
>
> Works for me, I use raid 5 three drives encrypted filesystems, root and
> everything else.  With an encrypted root filesystem the kernel line is a bit
> different but what is above will work for you.
>
> What does your fstab say about the root filesystem?
> do you have
>
> /dev/md0        /       ext4  blah.blah, blah

Yes, that is what my fstab file shows...minus the blah blah blah. It
has the proper parameters.