Disk Drives

Why is my HDD parking the read-write heads so frequently (clicking noises)?

The APM setting for battery mode

DISK_APM_LEVEL_ON_BAT=128

corresponds to the Ubuntu default and should cause no problems. Unfortunately drive manufacturers interpret the APM levels quite spaciously to save power.

Solution: try values > 128. See DISK_APM_LEVEL_ON_AC/BAT.

Why does my HDD not spin down?

Stopping the system disk for extended periods of time is unlikely to work, because applications and system daemons wake up the disk frequently. There is no real solution for this other than changing many applications and daemons.

How can I stop my 2nd HDD?

To spin down after 1 minute (= 12 · 5 seconds) idle time use:

DISK_SPINDOWN_TIMEOUT_ON_AC="0 12"
DISK_SPINDOWN_TIMEOUT_ON_BAT="0 12"

See DISK_SPINDOWN_TIMEOUT_ON_AC/BAT.

Why does my HDD always spin up when switching from AC to battery power (and vice versa)?

TLP applies configured APM levels and spin down timeouts upon every change of power source and upon suspend/resume. Writing the settings inevitably spins up the disk. To prevent this behaviour either disable the settings completely by commenting all of them (with a leading #) or use the special value keep for the specific disk.

See DISK_APM_LEVEL_ON_AC/BAT.

Why is my Crucial M4 SSD so slow on battery?

The Crucial M4 reduces performance according to the APM level. You may disable APM with

DISK_APM_LEVEL_ON_AC="255 255"
DISK_APM_LEVEL_ON_BAT="255 255"

Drive Bay: why is the optical drive not powered off on battery?

Possible causes are:

ThinkPad without UltraBay

SL/Edge models for instance.

Incompatible Laptop

At the time of writing this functionality is tested with ThinkPads only.