RAID1 - mkfs - Invalid argument passed

[Zbynek Cvach]

Hi all,

I am new in this place and I am in war with  RAID1.

raidtab
    raiddev /dev/md0
    raid-level 1
    nr-raid-disks 2
    nr-spare-disks 0
    chunk-size 4
    device /dev/sda6
    raid-disk 0
    device /dev/sdb1
    raid-disk 1

raid1.conf
    raiddev /dev/md0
    raid-level 1
    nr-raid-disks 2
    nr-spare-disks 0
    device /dev/sda6
    raid-disk 0
    device /dev/sdb1
    raid-disk 1


I do:
mkraid /dev/md0
    corret

raidadd /dev/md0 /dev/sda6 /dev/sdb1
    correct
    in /proc/mdtab: md0 : inactive sda6 sdb1 nnn blocks

raidrun -a
    correct?
    in /proc/mdtab is still: md0 : inactive sda6 sdb1 nnn blocks

mkfs /dev/md0
    invalid argument passed to ext2 library while setting up superblock

Do you know anybody what is wrong? The OS is RedHat 5.2 Apollo.
I'v try StarBuck too with this same result.

Thank you for any reply.
Zbynek Cvach