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odd problem with raid array

Hi Folks,

Still struggling to get this new box set up the way I'd like it:

- had to install a new kernel to see high memory (thanks!)

- took a while to figure out that a string of "devfs_mk_dev: could not 
append to parent for /disc" errors are not dangerous (apparantly they show 
up when putting root on LVM on RAID) - and that devfs is about to go away 
in newer kernels

- now wrestling with on remaining problem, and I'd appreciate any help 
anybody can offer:

I have four disks, several partictions each, with several raid-1 
(software) volumes defined on top of these, used as follows:

/boot (raid 1)
/     (LVM on raid 1)
/backup (LVM on raid 1)
swap  (raid 1)

Each of these is built with two active devices and one spare device.

Here's what's funny:
- all of these set up properly EXCEPT root.  Root comes up with its two 
active devices, but doesn't seem to even try to bind the spare device (no 
entry in the kernel log)

/etc/mdadm/mdadm.conf seems to be set up correctly (it was set up 
initially by the installer):
server1:/var/log# more /etc/mdadm/mdadm.conf 
DEVICE partitions
ARRAY /dev/md3 level=raid1 num-devices=2 spares=1 
ARRAY /dev/md2 level=raid1 num-devices=2 spares=1 
ARRAY /dev/md1 level=raid1 num-devices=2 spares=1 
ARRAY /dev/md0 level=raid1 num-devices=2 spares=1 

here's the relevant entry from the console display
###here's where /dev/md1 - my swap device is started
md: md1 stopped.
md: bind<sdc2>
md: bind<sdb2>
md: bind<sda2>
raid1: raid set md1 active with 2 out of 2 mirrors
mdadm: /dev/md1 has been started with 2 drives and 1 spare.

###and right afterwards is where /dev/md2, my root fs is strated
md2 stopped.
md: bind<sdc3>
md: bind<sda3>
raid1: raid set md2 active with 2 out of 2 mirrors
mdadm: /dev/md2 has been started with 2 drives.

in this case, it doesn't seem to even try to bind /dev/sdb3 - no error 
messages about it not being fresh, or anything - it just doesn't seem to 

note: after everything comes up, if I try:
mdadm /dev/md2 -a /dev/sdb3
it works just fine (as confirmed with mdadm --detail)

As a work-around, I guess I could mount it in a local init file, after 
everything else comes up, but that seems like a kludge.  I'd rather 
understand what's going on.  About the only thing I can think of is that 
something is going on early in the boot cycle, since there's a 
"root=/dev/mapper/rootvolume-rootlv" in my kernal boot config, that 
eventually maps onto /dev/md2.

Any thoughts, debug suggestions.

Thanks very much - I think this is the last nit I have to pin down before 
starting to put real apps on this box.


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