Open Stack

Hello,
There is a configuration setting called:
remove_unused_original_minimum_age_seconds

by which you can define the timeout by which used instances will be removed.
This instances are cached under:
/var/lib/nova/instances/_base/

see for example:
http://docs.openstack.org/developer/openstack-ansible/liberty/install-guide/configure-openstack.html

My first question is:
what is the value of this remove_unused_original_minimum_age_seconds
setting ? I think I somewhere saw that it is (or was) 24 hours but I
am not sure. is there a way I can query for this value (apart
from probing into the code).

My second question is:
I want to change the value of
remove_unused_original_minimum_age_seconds(assuming that it is indeed
24 or event 12 or 3 hours) to be 120 seconds or 60 seconds. I tried
adding an entry in /etc/nova/nova.conf saying
remove_unused_original_minimum_age_seconds = 60
And then restart the nova-compute service by:

service nova-compute stop
and then
service nova-compute start

but this seems not to achieve the expected result; I still see unused
images under  for time intervals way too larger than
60 seconds.

Can anyone advise about this ? should I restart additional nova services ?

Regards,
Kevin