So basically, you need to short circuit one of Docker's core features to get decent performance. I like it.
Not by default:
# docker run -i -t ubuntu bash
root@48dbef418f4c:/# echo foo > /bar
root@48dbef418f4c:/# exit
# docker restart 48dbef418f4c
48dbef418f4c
# docker attach 48dbef418f4c
root@48dbef418f4c:/# cat /bar
foo
root@48dbef418f4c:/#
Docker won't delete a container unless you tell it to.