RHEL5, at boot /dev/cdrom open fail

The problem is at boot time you may get a failed reference to /dev/cdrom

It is caused by the LVM mounting tools trying to probe a cdrom device.

You need to edit the LVM conf to "filter" out cdrom devices and not try to probe them.

How to reproduce the problem:

# lvdisplay  

 /dev/cdrom: open failed: No medium found

How to fix the problem:

# vi /etc/lvm/lvm.conf

You can only have [one] filter active at a time, the default probes everything.

Comment that filter line out, then add this filter line in:

filter = [ "r|/dev/cdrom|" ]