Laptops, power management, and Ubuntu

Laptops, power management, and Ubuntu

Posted Nov 11, 2007 13:58 UTC (Sun) by hmh (subscriber, #3838)
In reply to: Laptops, power management, and Ubuntu by tialaramex
Parent article: Laptops, power management, and Ubuntu

Did they know about this before it was widely reported ?

Sure. It is documented (well, if you buy good Hitachi drivers. I don't know about the other HD manufacturers. IMO, most of them are not even worth bothering with, as they don't publish the full HD firmware manual and spec sheet, anyway).

Is there any hardware or firmware bug involved ?

You asked the drive to enter the most agressive power management mode. It is doing exactly what you asked it to do. If you don't want it to act like that, don't tell the drive to use the most aggressive power management mode. So, it is not the drive's fault.

Do they consider the Load / Unload count to be a significant predictor of early drive failure (most SMART old-age counters aren't very indicative of likely failure) ?

AFAIK, ramp-based head unloads do stress the head assembly in a way that will slowly make it far less reliable, yes.

Is the behavior (not just seen in Ubuntu) where these cycles occur very frequently actually pathological, or was it considered an acceptable consequence for power saving ?

How smart it is for a distro or a BIOS vendor to enable the most aggressive power management mode of a drive? Especially when nothing is being done to reduce disk accesses to a level compatible with that power management level?

Do they intend to alter the power on configuration of future drives in the light of these results ?

I hope they don't. I'd rather laptop and distro vendors stop enabling it when the entire system is not prepared to deal with it.

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   You asked the drive to enter the most agressive power management mode.

I did no such thing. I had not touched any hard drive settings in the BIOS or OS until my
cycle count was over a million. Linux came pre-installed on this computer, so my role is pure
"user".

Let's be very clear that the user is the innocent victim here. Any posting that blames the
user is quite unfair. The responsibility to avoid this problem may lie with the drive
manufacturer, the laptop manufacturer, whoever installed Linux on the laptop, or even with the
distro (although that does not appear to be the case). But definitely not with the end-user,
who just turned on the laptop and expected it to work.

I don't remember any of the online suggestions for mitigating this problem having mentioned
checking BIOS settings to see if the power management can be made less aggressive. The article
above certainly didn't. I'll try that next time I reboot.

Kevin

I hate english.

Anyway, I wanted to use "you" in the PoV of the HD.  I didn't mean "you, the human".

I very much doubt any user would want the most aggressive power management mode of the
hardware enabled by default.  It is annoying, it kills the hardware that much faster, and it
introduces a lot of latencies.  On the other hand, it is extremely useful when you know what
you are doing, and enable it on purpose...

This, of course, makes the whole deal of enabling it by default (done by whomever: distro or
platform vendor), worse.