Bug 59695 ("default value in power.sh potentially kills laptop disks") is about not preventing bad behaviour of drives (high Load_Cycle_Count numbers) on (laptop) harddrives.

Because the bug report has 150 comments already, I've tried to summarize it here.

There appear to be two issues here: HDD spin down and "Power cycling", whereas the first one has a relative short default (60 seconds), but the latter one gets the most complains (it's about Load_Cycle_Count).

The disk Load_Cycle_Count issue appears to be caused by a combination of two problems -- The first is overly-aggressive power management from what might be considered buggy hardware. The second is that Ubuntu appears to be touching the hard drive on a regular basis for one reason or another.

Note 1: In sections below relating to how to prevent damage to your hard disk, you should replace $HDD everywhere with your device, e.g. "/dev/sda" or "/dev/hda". If you have several harddrives, you need to change it accordingly and duplicate lines in workarounds.

Note 1: The kernel wiki gathers info about drives with too aggressive power saving defaults. A script called "storage-fixup" is also available. https://ata.wiki.kernel.org/index.php/Known_issues#Drives_which_perform_frequent_head_unloads_under_Linux

Affected hardware

Machine Hard Disk Ubuntu Other OS Workaround Notes Acer Aspire 1642 WLMi N/A Ubuntu=YES N/A N/A Acer Aspire 1662wlm Hitachi 5k100 60 GB Ubuntu=YES N/A N/A Acer Aspire 3610 N/A Ubuntu=YES N/A N/A Acer Extensa 5210 N/A Ubuntu=YES N/A N/A Acer Travelmate 4010 Hitachi IC25N060ATMR04 Ubuntu=YES XP=YES N/A Airis N1212 N/A Ubuntu=YES N/A N/A acpi=off Apple Powerbook G4 Seagate Momentus 5400.2 100GB Ubuntu=YES N/A N/A Apple MacBook Pro C2D Fujitsu 160GB Gutsy=YES MACOSX=YES N/A Asus A6Q Seagate ST980811AS Hardy=YES XP=NO -B 254 Asus 1000HA Seagate ST9160310AS eeebuntu=YES XP=NO N/A Asus G1S-A1 Hitachi HTS541616J9SA00 Ubuntu=YES N/A N/A Compaq Evo600N N/A Ubuntu=YES N/A N/A Dell D620 N/A Ubuntu=YES N/A N/A Dell Inspiron 1501 N/A Ubuntu=YES N/A N/A Dell Inspiron 1525n WDC WD2500BEVS-75UST0 Hardy=YES Gutsy=NO,Fedora9=Yes -B 255 Dell Inspiron 9400 Samsung 120GB Ubuntu=YES N/A N/A Dell Inspiron 6400 Samsung HM120JI Gutsy=YES N/A N/A Dell Latitude C640 Western Digital 40GB Gutsy=YES XP=NO N/A Dell Latitude c840 Hitachi DK23EA-30 Ubuntu=YES N/A N/A Dell Latitude D630 N/A Ubuntu=YES N/A -B 254 Dell Vostro 1000 Seagate ST9120822AS Ubuntu=YES N/A N/A Dell Vostro 1400 N/A Ubuntu=YES N/A -B 254 Dell Vostro 1500 Seagate ST9160823AS Gutsy=YES XP=YES Dell XPS M1330 N/A Hardy=YES N/A -B 254 Dell XPS M1330 Western Digital WD1200BEVS-75UST0 Hardy=YES N/A -B 255 Dell XPS M1330 WDC WD2500BEVS-75UST0 Hardy=YES N/A -B 254 XP=YES Dell XPS 1530 N/A Ubuntu=YES N/A N/A Gateway MT6451 Western Digital WD1200VE Gutsy=YES N/A N/A HP nx6325 Samsung HM250JI Hardy=YES Vista=NO -B 254 HP nx6325 Fujitsu MHV2060BH Gutsy=YES N/A -B 255 HP nx6325 Hitachi HTS541080G9SA00 Ubuntu=YES N/A N/A HP nc8430 Samsung 250GB Hardy=YES N/A N/A HP nw9440 Seagate ST910021AS Edgy=YES N/A N/A HP dv6500 Western Digital WD800BEVS Ubuntu=YES N/A -B 255 HP dv6602au N/A Ubuntu=YES N/A N/A HP compaq 6820s Hitachi HTS541616J9SA00 Hardy=YES Vista=NO -B 255 HP dv6614tx N/A Hardy=YES N/A -B 255 MSI Wind U100 Western Digital WD800BEVS Hardy=YES N/A -B 254 Thinkpad Z60m Hitachi HTS541080G9SA00 Gutsy=YES N/A N/A Thinkpad R52 Hitachi HTS541060G9AT00 Gutsy=YES N/A -B 192 Thinkpad 600E Hitachi DK239A-65B Ubuntu=YES N/A N/A Thinkpad Z61t Toshiba MK1032GSX Gutsy=YES N/A N/A Thinkpad T60 Hitachi HTS541080G9SA00 Gutsy=YES N/A N/A Thinkpad T23 Seagate ST92811A Ubuntu=YES N/A N/A Thinkpad R50e Hitachi HTS541060G9AT00 Feisty=YES N/A N/A Thinkpad T42 Samsung HD Ubuntu=YES N/A -B 254 Thinkpad R61 Seagate ST9160821AS Hardy=YES N/A N/A Toshiba A100 Toshiba MK1234GSX Ubuntu=YES N/A -B 254 On battery power Toshiba P205 Fujitsu MHW2120BH Gutsy=YES N/A -B 255 VIA Epia EX10000EG Western Digital WD10EACS Feisty=YES N/A N/A N/A Hitachi HTS541616J9SA00 Ubuntu=YES Vista=YES N/A N/A Hitachi HTS541210H9SA00 Ubuntu=YES N/A N/A N/A Hitachi HTS541010G9SA00 Ubuntu=YES N/A N/A N/A Seagate ST9100824AS Ubuntu=YES Vista=YES XP=YES N/A Seagate ST9160821AS Ubuntu=YES N/A N/A N/A Seagate ST9120822AS Hardy=YES XP=NO N/A N/A Travelstar 7K100 60GB Ubuntu=YES N/A N/A N/A Toshiba MK8037GSX Ubuntu=YES Fedora=NO OpenSUSE=NO N/A Toshiba MK3006GAL Ubuntu=YES N/A -B 254 N/A WDC WD5000AACS-00ZUB0 N/A N/A N/A

Check

You can check the current value of Load_Cycle_Count of your harddrive(s) using:

sudo smartctl -a $HDD | grep Load_Cycle_Count

(You need the smartmontools package for this. I also had to enable SMART monitoring for my drives using sudo smartctl -s on $HDD )

The values for this differ a lot (e.g. it's 0 on my desktop), but it goes up to > 600.000 for others, depending on the lifetime. TODO: add a section with sample values (including the value of Power_On_Hours).

What Ubuntu does

It appears to be the official policy of Ubuntu that by default, Ubuntu should not adjust any power management settings of the harddisk. Unfortunately, this policy has two negative effects: It leaves quite a few people with broken hard drives that would otherwise not be broken, and it quite simply makes people who love Ubuntu feel neglected. This issue has been going on a long time.

The problem appears to be that some manufacturers' defaults are too aggressive and that Ubuntu might cause too many unbuffered disk accesses -- the combination of which can cause over a thousand parks a day on some systems.

In /etc/acpi/power.sh, laptop mode gets handled. If it gets enabled, hdparm is called with "-B 1", if it gets disabled with "-B 254". 254 is the least aggressive setting. 255 is off, but does not work for all disks.

In power.sh also the spindown timeout gets set, according to SPINDOWN_TIME from /etc/default/acpi-support (default: 12). This results in spinning down the harddrive after 12*5=60 seconds of inactivitiy. This does not influence Load_Cycle_Count however.

apm

"/etc/apm" is not supposed to be used, but if it would get, it sets spindown to 60 seconds - but does not affect the general APM setting (hdparm -B). (there's a bug, which also used "power_conserve" here, if on_ac_power return "don't know" - bug 156893)

Debug

Blue has created a script, which acts as a wrapper around hdparm and logs, where it's called (including its arguments) From his report, it appears that hdparm always gets called through apm or the init script (the logfile excerpt appears to be from booting).

TODO: provide said helper script, allowing others to help to debug this.

Workaround

Various workarounds have been provided that involve adjusting or even turning off power-management of the hard drive. Please keep in mind that this can do more harm than good, so only apply them if you exactly understand what you are doing.

Try hdparm -B 255 $HDD or hdparm -B 254 $HDD . (255 is supposed to disable APM, but it does not work for some; so 254 sets it to the less aggressive setting)

There are different methods to keep this setting after reboot/resume. Your mileage may vary. There may be more workarounds in the bug report, but essentially, all are using "hdparm -B" to change the apm handling of the harddrive.

http://ubuntuforums.org/showpost.php?p=3675960&postcount=26 UbuntuDemon I brought some of these proposed fixes together in the hope that is easier to apply for users who are suffering from this problem



Force hdparm values in pm-utils hooks

Edit /etc/hdparm.conf and put there:

$HDD { apm = 254 }

Create executable file /etc/pm/sleep.d/99fixpark with the following lines:

case "$1" in resume|thaw) hdparm -B 254 $HDD >/dev/null 2>&1 ;; *) ;; esac

Don posted another workaround: Install laptop-mode-tools and set CONTROL_HD_POWERMGMT=1 in /etc/laptop-mode/laptop-mode.conf (https://launchpad.net/ubuntu/+source/acpi-support/+bug/59695/comments/19) Here's another more verbose setup of laptop-mode-tools from Michael: https://launchpad.net/ubuntu/+source/acpi-support/+bug/59695/comments/63

An easy, step-by-step walkthrough for a situation-sensitive solution (AC/batteries/heat) can be found here: http://vale.homelinux.net/wordpress/?p=199

Proposed fixes

FIXED: Converted most remaining 255's to 254s, and added an explanation.

Conclusion

This bug report has attracted a lot of concerned Ubuntu users and it seems quite clear from the user feedback, that other operating systems/distributions handle this better. However, the workaround should be quite simple and this wiki page is a first attempt, to fix this for the better.

Misc

ubuntu_demon has put together a list of TODOs: https://launchpad.net/ubuntu/+source/acpi-support/+bug/59695/comments/81

Please leave any comments/additions here. You may also edit the page directly, but please try to be clear and helpful. The problem has been confirmed and we know that it's a critical thing - please do not repeat that the bug status should be critical.

Could you kindly explain how to diagnose whether the settings on a system, at a point of time, are correct. I have followed the instructions but still find the load cycle count increasing. How do I diagnose the problem?

I think the 99-fix-park.sh scripts should be executable. If this is the case then I think we should add a note to the workaround.