[laptop-mode] Logging?

[Schnobs]

Hello,

Short question: how can I monitor when (or how often) the disks are spun 
up and down? If I can turn on logging somewhere, I fail to see that switch.

Long background: I'm running laptop-mode not on a laptop, but on a 
desktop machine (actually my home server, coveniently placed in the 
broom cupboard). I'm trying to find settings that will keep the disks 
powered down when the box is idle without causing too many start/stop 
cycles per day.

Regards,
Schnobs