[Nut-upsuser] RAID readonly before final shutdown

[Gaspar Bakos]

Hi,

The entire OS I am using is running on software RAID-1. Before killing
the power of the UPS, I issue:

/sbin/mdadm --readonly $RAIDDEV
on all the RAID devices I have.

This, however, does not seem to be enough, and when i power the system
back on, the RAID arrays are not clean, and a long syncing starts. A
last step is missing; something like marking the arrays that they are
clean. I see this happening for a flash of a second when i tell the PC
to "/sbin/poweroff", i.e. "halt -p". The very last second, before the
ATX power is turned OFF, the kernel does something to the md arrays.

My questions are:
1. What exactly is this last step?
2. Can I achieve it manually by sth like
 echo *** > /proc/***
or by using mdadm?

Cheers
Gaspar