apt install quota

quotacheck quotaon requota

echo '/dev/md0 /mnt/raid/ ext4 usrquota,grpquota 0 0' » /etc/fstab

mount -o remount,rw /mnt/raid/

chmod 777 /mnt/raid/

quotacheck -vu lisa

quotaon -a

edquota -u lisa

su - lisa

dd if=/dev/zero of=lisadile

dd: writing to 'lisadile': Disk quota exceeded