I have small server, mainly for backups. System is Ubuntu 9.10. Because backup is once a day, most of the time the server is idle. So I wanted disk to spin down, but it is always running. I can spin it down by
hdpparm -y /dev/sda
But then after few seconds it is spinning again.
I tracked (by inotify) that usually it is /var/spool/postfix/<something>
accessed. Looks like postfix reads it every few seconds. Can I force postfix to access disk not so frequently?