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

[Baho Utot]

On Monday 11 January 2010 13:36:06 Carlos Williams wrote:
> 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.

I have three 1TB drives thats an overnite one
> 
> >> #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?
> 

I have a blank mdadm.conf

> >> */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.

From my working system in /etc/rc.conf
MODULES=( !net-pf-10 !snd_pcsp !pcspkr !usblp b43 powernow-k8 )  
notice no raid there.

> 
> >> - 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.
> >

Notice from my working system /etc/mkinitcpio.conf

HOOKS="base udev sata raid encrypt filesystems"


> > 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.

The system must already have the raid array assembled otherwise it could not 
read /etc/mdadm.conf let alone the init or the inittab files

> 
> > 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.
> 

Ok

Try the params on the /boot/grub/menu.lst line