mdadm cannot stop md0, resources busy
 

My md0 raid 5 has 4 drives. 2 drives failed and I want to take them out.

"fdisk -l" does not show those 2 failure drives. So I tried to stop the raid using "mdadm --force --stop /dev/md0"
but it cannot be stopped, resources busy.

is there other way to force it stop?

You have to unmount the array before stopping it. Note that you should check your hardware documentation for the proper procedure to remove disks from a live system (hint: if the documentation does not mention hot-swapping, you shouldn't try). Also, 2 failed drives in a raid 5 array means the array is unrepairable.