who is setting my link_power_management_policy?

henfri

11/26/23, 3:53 PM

I am experiencing issues with my sata connection. Thus, I want to change /sys/class/scsi_host/host*/link_power_management_policy to max_performance.

For that, I execute on boot a script:

cat /etc/openmediavault/sata_power.sh
for i in /sys/class/scsi_host/host[012345]/link_power_management_policy; do echo max_performance >$i; done
cat /sys/class/scsi_host/host*/link_power_management_policy

I see that this script is running and also the output is max_performance (I get the output by mail).

Nevertheless, if I log in to the machine after boot, I get med_power_with_dipm for all hosts.

Who is changing that setting?

The only other file that I find in /etc that includes power_management_policy is

/etc/udev/rules.d/hd_power_save.rules
ACTION=="add", SUBSYSTEM=="scsi_host", KERNEL=="host*", ATTR{link_power_management_policy}="max_performance"

Best regards, Hendrik

259

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electrical-power

sata

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Server

shodanshok

11/26/23, 4:10 PM

It probably is a kernel default. From the docs:

med_power_with_dipm – best balance between power saving and performance (Kernel ≥ 4.15 required, then recommended)

Default when unconfigured: “med_power_with_dipm max_performance” (AC), “med_power_with_dipm min_power” (BAT)

+ 2

henfri

11/27/23, 2:12 PM

That is the default of TLP. But I have uninstalled TLP. Indeed, this has changed the situation. Now, After Boot I have min_power. This although I have a crontab entry that sets it to max_power (see above) at Boot. The problem is, that I have SATA Errors already during the boot. I would like to rule out this setting. Thus, I need to ensure that already during boot the setting is max_power.

shodanshok

11/27/23, 5:39 PM

Try adding the following kernel boot option: `libata.force=nolpm`

Elon Musk

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EN: who is setting my link_power_management_policy?

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