Saving a bit on power use: putting disks to sleep again / 2015-07-30

I noticed one of the harddisks in the home server greenblatt wasn't in standby mode when idle for a long time. This was noticeable since the UPS load value was a bit higher than I expect for a complete idle machine.

A few years ago I set up spindown to set the disks to standby on inactivity and this wasn't happening. A peek at the internal statistics turned out that since the two ubuntu upgrades in april this disk wasn't going into standby mode. It turned out that since the kernel upgrades it doesn't listen to sg_start --stop anymore so I had to change the relevant part of /etc/spindown.conf to:

[Disk 0]
id = ata-WDC_WD15EADS-...
spindown = 1
command = hdparm -y

And a few watts are saved again. The interesting part is that the sg_start --stop command still works fine for the WDC_WD10EADS disk.