CentOS - May 2007 - SCSI device not detected after 4.5 update

After updating to Centos 4.5, I found that one of the LUNs on an
external SCSI array wasn't being detected.  If I add the device manually
after boot

echo "scsi add-single-device 0 0 1 1" > /proc/scsi/scsi

it is detected.  I can then use the LVM tools to activate it and then
mount the LV on the device.

It doesn't seem to be kernel related as I rebooted into a 4.4 kernel and
the same thing happened.  There's no error message I can see at boot, it
just doesn't see the device.

It's using a QLogic HBA but with the upstream module, not the
out-of-tree QLogic one.  It worked fine under 4.4.

I suspect changes to dmsetup and/or multipath.  Has anyone else seen
something similar?

Adam
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Adam Huffman wrote:
> After updating to Centos 4.5, I found that one of the LUNs on an
> external SCSI array wasn't being detected.  If I add the device
manually
> after boot
>
> echo "scsi add-single-device 0 0 1 1" > /proc/scsi/scsi
>
> it is detected.  I can then use the LVM tools to activate it and then
> mount the LV on the device.
>
> It doesn't seem to be kernel related as I rebooted into a 4.4 kernel
and
> the same thing happened.  There's no error message I can see at boot,
it
> just doesn't see the device.
>
> It's using a QLogic HBA but with the upstream module, not the
> out-of-tree QLogic one.  It worked fine under 4.4.
>
> I suspect changes to dmsetup and/or multipath.  Has anyone else seen
> something similar?
>
> Adam
Adam,

I'm not sure of the why, but this link may help solve the problem.  
Maybe the initrd for the latest kernel was not built with the max_luns 
option.

http://publib.boulder.ibm.com/infocenter/dsichelp/ds8000ic/index.jsp?topic=/com.ibm.storage.ssic.help.doc/f2c_linuxlunconfig_2hsaga.html


Read the man page on mkinitrd.   I'd rename the originals before 
rebuilding.  If you're daring, you'll the -f option to mkinitrd to 
rebuild over the originals.

Bob...