Comment 22 for bug 952556

After I added "apm_battery = 255" to hdparm.conf per Colin's request, and rebooted my system, logged in then left it alone for 10 minutes, the HD's start/stop count DOESN'T INCREASE ANYMORE.

So this is effectively a "quick & dirty fix".

hdparm -I confirms : « Advanced power management level: disabled »

However disabling it completely doesn't sound like the best solution, it might be better to leave *some* HD power management active, but with values that doesn't allow the disk to spin down every so often !

"man hdparm" suggests that -B values >= 128 do not allow spindown, while -S values allow setting the desired timeout precisely.

So aggressive values that allow a disk to spin down after a couple of seconds should never be a default ! And upgrading from Oneiric to precise made this happen... :-/

Checking /lib/hdparm/hdparm-functions shows that battery -B default is 127 (spindown allowed).

That is not necessarily wrong, but should probably be followed by something by -S36 (that makes spindown after 3 minutes of inactivity) or no less than -S24 (would be 2 minutes), while I see no default value for -S ?!

A typical Linux machine usually accesses disks at least once a minute (unless laptop-mode tools are in use and syslogs are delayed, etc...) so spinning a disk down in a shorter amount of time really risks causing an undesired and disk-killing behaviour...