On 06/24/2010 11:03 PM, Dan Williams wrote:

This is expected without the --force option:

--force
               Insist that mdadm accept the geometry and layout
specified without question.
               Normally mdadm will not allow creation of an array with
only one device, and
               will  try  to create a RAID5 array with one missing
drive (as this makes the
               initial resync work faster).  With --force, mdadm will
not  try  to  be  so
               clever.

   

The manpage you quoted says mdadm will not create a raid5 array with 
only one device.
However in my case I have --raid-devices=2 and both /dev/sdd1 and 
/dev/sdb1. So I should be ok with a raid5 and 2 devices?
The reason I am not using raid1 is because a want to add more drives 
later on.

Best regards,
Markus




mdadm --create --verbose /dev/md1 --chunk=64 --level=5 --raid-devices=2 
/dev/sdd1 /dev/sdb1