Tell the system that my disks will be raided:

Correct autoraid:

/sbin/fdisk /dev/sdd1
p
t
fd
w

do this for each disk:

/sbin/mdadm --create --verbose --raid-devices=3 --level=5 /dev/md0 /dev/sdd1 /dev/sde1 /dev/sdf1
/sbin/mdadm --detail --scan > /etc/mdadm.conf

# Check

/sbin/mdadm --detail  /dev/md0

/sbin/mkfs.ext3 /dev/md0
mount /dev/md0 /dataxrd

Correct fstab:

/dev/md0                /dataxrd                   ext3    defaults        0 0

Make RAID5 from existing disks (which were in RAID5 before)

/sbin/mdadm -A  /dev/md0 /dev/sdd1 /dev/sde1 /dev/sdf1
/sbin/mdadm --detail --scan > /etc/mdadm.conf