Comment 7 for bug 1484497

It's questionable if it should be considered a bug or not. The culprit is smartd. Ironically I used the package smartmontools 6.3+svn4002-2 to get smartctl, for testing if something wakes up a green drive. Despite the policy to autostart everything by default, that can be autostarted for better or worse, it's to consider if the default configuration, to poll every 30 minutes, is a wise decision. By an EU Regulation all external hard disk drives are forced to spin down and go to sleep after a while. I disabled smartd.service, any unneeded service is unwanted on my machine.

After disabling it, nothing does wake up a green drive anymore.

[root@moonstudio weremouse]# echo;date;t=10800;y=$(smartctl -A /dev/sdc|grep Lo|awk '{print $NF}');sleep $t;x=$(smartctl -A /dev/sdc|grep Lo|awk '{print $NF}');printf "\n$(uname -rm)$(lsb_release -d|cut -f2 -d:|cut -f1 -d"(")\n$x-$y=$((x-y)) spins in $(($t/60/60)) hours\n\n";date

Mon Aug 24 15:00:50 CEST 2015

3.10.61-rt65-1-moonstudio x86_64 Ubuntu Wily Werewolf
15377-15376=1 spins in 3 hours

Mon Aug 24 18:00:56 CEST 2015

The only spin is caused by smartctl, when it was executed on demand, to finish the test.

How I noticed that smartd is the culprit:
https://lists.ubuntu.com/archives/ubuntu-devel-discuss/2015-August/015782.html

A note regarding smartd:
https://lists.ubuntu.com/archives/ubuntu-devel-discuss/2015-August/015784.html