[CentOS] migrate ext3 to ext4

Hi all,

I issued the commands on a single disk system:
with two partitions / is linux sda1 and /home is sda3
yum -y update
yum -y install e4fsprogs
                reboot
umount /home
tune2fs -O extents,uninit_bg,dir_index /dev/sda3
e2fsck -yfDC0 /dev/sda3

That worked just fine.
I then had a different system that is software raid.
where / is linux and md0 and /home is md1
yum -y update
yum -y install e4fsprogs
                reboot
umount /home
tune2fs -O extents,uninit_bg,dir_index /dev/md1
at this point I get an error that
invalid options for tune2fs

Why is that and what to do next... The single disk sda3 worked fine.
shouldnt the md1 work also.

Thanks,

Jerry