replacing an ide drive with an sata one in an raid 5 array
before i had 4 ide drives
hda - wd400bb
hdb - gb200p0
hdc - gb200p0
hdd - wd2500jb

and now i have another wd 250G sata one


mdadmin --manage --setfaulty /dev/md0 /dev/hdc

mdadm /dev/md0 -r /dev/hdc

reboot

add the new drive after i have created an new partition with fdisk with the same siz
fdisk /dev/sda

mdadm /dev/md0 -a /dev/sda

watch it with cat /proc/md0
i created new raid with the space left after using 200G from each drive for
raid5

mdadm --create --verbose /dev/md1 --level=1 --raid-devices=2 /dev/sda2 /dev/hdd2