Re: mdadm -A /dev/md3 fails

On Monday September 9, marc_news@merlins.org wrote:

On Mon, Sep 09, 2002 at 04:20:14PM +1000, Neil Brown wrote:

quoted

That is part of the reason that I wrote mdadm.  It can do the right
thing for you.

Apparently it can, but I'm having issues with it:

My conf file says:
DEVICE /dev/scsi/host*/bus*/target*/lun*/part*
ARRAY /dev/md3 level=raid5 num-devices=7 UUID=7f69d69c:2d523219:4f3d1ea7:9b7f4057 devices=/dev/scsi/host3/bus0/target8/lun0/part1,/dev/scsi/host3/bus0/target9/lun0/part1,/dev/scsi/host3/bus0/target10/lun0/part1,/dev/scsi/host3/bus0/target11/lun0/part1,/dev/scsi/host3/bus0/target12/lun0/part1,/dev/scsi/host3/bus0/target13/lun0/part1,/dev/scsi/host3/bus0/target14/lun0/part1

gargamel:/etc/mdadm# mdadm -A  -v /dev/md3
mdadm: No identity information available for /dev/md3 - cannot assemble.

Any idea why 
mdadm -A -v /dev/md3 doesn't work?

As Derek says, add "--scan" to tell it that it is allowed to look in
the config file.
Also, get rid of the "devices=...." part of the ARRAY line or it will
fail if any of the devices change address.

Am I supposed to actually start the device with
mdadm -A  -v /dev/md3 /dev/scsi/host3/bus0/target*/lun0/part1 ?

That would probably work..

or
mdadm -A  -v -u 7f69d69c:2d523219:4f3d1ea7:9b7f4057 /dev/md3 ?

That wouldn't.  Would would need to to mdadm where the devices are:

mdadm -A  -v -u 7f69d69c:2d523219:4f3d1ea7:9b7f4057 /dev/md3 /dev/disk/*/part*

would work.

(I thought mdadm would get that data from the config file)

Only when you tell it to.  If that isn't clear from a second reading
of the man page, I would appreciate suggestions on how to make it more
clear.


NeilBrown