Laptops, power management, and Ubuntu [LWN.net]

Laptops, power management, and Ubuntu

Posted Nov 13, 2007 15:21 UTC (Tue) by mdz@debian.org (subscriber, #14112)
In reply to: Laptops, power management, and Ubuntu by kevinbsmith
Parent article: Laptops, power management, and Ubuntu

Don't be silly; reread the comments I was responding to.  I addressed two points:

1. That Ubuntu provided two conflicting tools for enabling laptop mode (it hasn't)

2. That enabling laptop mode would be a good way to prevent a high number of load/unload
cycles (it isn't)

I didn't suggest that you remove the tools for laptop-mode, though I did recommend against
enabling it.

If you want to set default power management settings for your disk in Ubuntu, /etc/hdparm.conf
is probably the best way to go about it.

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Laptops, power management, and Ubuntu

Posted Nov 13, 2007 17:15 UTC (Tue) by kevinbsmith (guest, #4778) [Link]

I apologize for misunderstanding which of the two laptop modes you were talking about. Still,
it's clear that neither is causing my problems. And other folks have suggested that enabling
laptop mode (with appropriate settings) is a way to solve the problem. (Some folks say the
hdparm -B setting is ignored if you are not in laptop mode).

I appreciate the pointer to /etc/hdparm.conf. It's not mentioned on Ubuntu's wiki page, and I
don't remember seeing it anywhere else. I just added this to mine:

/dev/sda {
        apm = 254
        spindown_time = 240
}


Unfortunately, I can't find any way to confirm that I added it correctly. I have no idea
whether those commands are in effect or not. I rebooted.

But my cycle count continues to increase by 4/minute, so it hasn't solved my problem.

I also checked my BIOS, and there are no settings there to control how the hard drive behaves.
And I re-ran hdparm directly (-B 254 and -S 240), and my cycle count continues to increase at
the same rate.

Laptops, power management, and Ubuntu

Posted Nov 23, 2007 19:52 UTC (Fri) by kevinbsmith (guest, #4778) [Link]

Quick update, in case it helps someone else. It seems that my Samsung drive ignores hdparm
settings unless you first do:

  sudo smartctl -o on /dev/sda

Don't ask me why. It makes no sense. But it worked. My load cycle count has finally stopped
increasing. At this point, my drive seems to be ignoring the hdparm -B parameters (stuck at
128 according to hdparm -I), but seems to be paying attention to -S (not fully confirmed).
When I suspended for 10 minutes, my load cycle went up by exactly one, which is a good sign.

Here is my forum post (basically what I just said here):
  http://ubuntuforums.org/showpost.php?p=3825166&postco...

At this point, I suspect that if I can get my system to stop accessing the drives every few
seconds, the heads will park when idle, as they should. Next quest: Find a good guide to how
to configure relatime. Why is that so hard to find?