what went wrong?

[Max Waterman <davidmaxwaterman@fastmail.co.uk>]

Hi,

I've set up raid on my fc3 box using mdadm.

I have 3 arrays - a RAID0 and two RAID5s, which are md0, md1, and md2 
respectively.

Initially, I had a problem where only md0 was being assembled at boot 
time. It seemed to revolve around missing /dev/md[12] devices files. I 
fixed that by adding a call to '/sbin/MAKEDEV md' just before the call 
to mdadm in /etc/rc.sysinit, but it creates many /dev/md* files when I 
only really need three.

However, I since discovered the 'auto' parameter - from the mdadm man page :

auto=  This  option  declares to mdadm that it should try to create
        the device file of the array if it doesn’t already exist, or
        exists but with the wrong device number.

        The  value  of  this option can be "yes" or "md" to indicate
        that a traditional, non-partitionable  md  array  should  be
        created,  or "mdp", "part" or "partition" to indicate that a
        partitionable md array (only  available  in  Linux  2.6  and
        later)  should be used.  This later set can also have a num-
        ber appended to  indicate  how  many  partitions  to  create
        device files for, e.g.  auto=mdp5.  The default is 4.

so I tried to use that.

..but that didn't seem to work very well. I don't know exactly what went 
wrong with using this, but it seemed to me like there was a problem with 
the device numbers (I think the drives were being associated with the 
wrong array or something)....so, I figured I'd try the super-minor 
option too, but that didn't work very well. I seemed to lose a drive in 
each array (which I later mdadm --add'ed back in - takes ages to fix 
itself though :( ).

So, I put removed the 'auto' and 'super-minor' options and put the 'fix' 
back into rc.sysinit. Works fine again, but I can't think it is not a 
real fix.

I am just wondering what I did wrong and what is the correct method for 
creating the devices above md0.

Can someone enlighten me?

Thanks.

Max.
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