Your UPS won't accept a timer value to wait before actually cutting
power? That would probably be ideal, issue the power off command with
something like a 30 second timeout, which would give the system time to
power off cleanly first.

-Tim

Niccolo Rigacci wrote:

Hello,

I'm facing this problem:

when my Linux box detects a POWER FAIL event from the UPS, it 
starts a normal shutdown. Just before the normal kernel poweroff, 
it sends to the UPS a signal on the serial line which says 
"cut-off the power to the server and switch-off the UPS".

This is required to reboot the server as soon as the power is 
restored.

The problem is that the root partition is on top of a RAID-1 
filesystem which is still mounted when the program that kills the 
power is run, so the system goes down with a non clean RAID 
volume.

What can be the proper action to do before killing the power to 
ensure that RAID will remain clean? It seems that remounting 
the partition read-only is not sufficient.