Re: raid 1 setup.

[Alexei Chetroi <debian@lexa.uniflux-line.net>]

On Wed, Sep 01, 2004 at 03:44:22PM -0500, Roger wrote:
> Date: Wed, 01 Sep 2004 15:44:22 -0500
> From: Roger <grunky@rockriver.net>
> To: debian-user@lists.debian.org
> Subject: Re: raid 1 setup.
> 
> Roger wrote:
> 
> >I'm trying to get raid 1 going on my Sarge unstable box.
> >
> >When I installed raidltools2 and mdadm doing a /proc/mdstat gave the 
> >following
> >
> >root@post2:/etc/network# cat /proc/mdstat
> >Personalities : [raid1]
> >read_ahead 1024 sectors
> >md2 : active raid1 ide/host0/bus0/target1/lun0/part3[1]
> >     3148672 blocks [2/1] [_U]
> >
> >md1 : active raid1 ide/host0/bus0/target1/lun0/part2[1]
> >     7269312 blocks [2/1] [_U]
> >
> >md0 : active raid1 ide/host0/bus0/target1/lun0/part1[1]
> >     25728000 blocks [2/1] [_U]
> >
> >
> >The thing is I have yet to create any md devices and my
> >
> >/etc/raidtab   <-which raidtools doesn't use - but I checked anyway
> >/etc/mdadm/mdadm.conf
> >
> >files are empty..
> >
> >How do I get rid of these bogus md devices?  I'm at a loss as to where 
> >the are configured, and that mdadm doesn't seem to have a erase or 
> >delete function to it
> 
> I finally got around to removing the md devices even though I had a 
> empty raidtab
> 
> raidstop /dev/mdx
> 
> That remove the raid entries in /proc/mdstat, while preserving the md 
> devices in /dev - from their I was able to create new raid devices.

  See http://alioth.debian.org/projects/rootraiddoc/ for some docs
regarding root on raid. I don't know about raidtools2, but mdadm may
operate without config file at all, if you know what're you doing. See
man mdadm, it contains all you need to know. For example, assuming you
have two drives /dev/hda and /dev/hdc having two partitions part1
and part2 of type 0xfd (raid autodetect) on each drive. Than to create raid1,
mirror with mdadm you do next:
mdadm --create /dev/md/0 --level raid1 --raid-devices 2 --spare-devices 0
/dev/hda1 /dev/hdc1

(make sure there're modules raid1 and md inserted with modprobe)
to create next md device you run:
mdadm --create /dev/md/1 --level raid1 --raid-devices 2 --spare-devices
0 /dev/hda2 /dev/hdc2

to stop a MD: mdadm --stop /dev/md/0
to assemble specific MD: mdadm --assemble /dev/md/0 /dev/hda1 /dev/hdc1
or mdrun to assemble all available raids.

After that, see rootraiddoc how to create mdadm.conf

  Good luck!

--
Alexei Chetroi