rw-mount necessary while assemble?

Hi!

is it really necessary to have /dev writeable when running mdadm --assemble --scan?

seems, that mdadm creates temporary nodes for the devices, even if there're already usable nodes...

any option that disables this need?

(want to call fsck -a during boot, but this needs ro-mount of root, where /dev is on, but this make only sense, if the md-devices are up and running)

w.