Laptop Hardrive Killer Bug

I previously blogged about a problem I had with my harddrive. Turns out the harddrive was dying. I confirmed it with hutil 2.0.3 from the Ultimate Boot CD. Now I am the proud owner of a Western Digital WD2500BEVS.

Turns out that I was right that there was something buggy going on. I discovered this bug report (people are blogging about this bug and it was even mentioned on the Digg) : https://bugs.launchpad.net/ubuntu/+source/acpi-support/+bug/59695

I have had laptop-mode enabled for a long time. Apparantly this caused my harddrive to get a Load_Cycle_Count of 241.493 in 1 year time. This is what probably caused my harddrive problems.

laptop-mode is disabled by default. If you have enabled laptop-mode (in /etc/default/acpi-support) you should definitely disable it!

Too aggressive powermanagement settings by laptop-mode will cause the head of your harddrive to park and unpark too often. Your harddrive is designed to last a certain amount of these park/unpark cycles and will eventually fail.

Some people who didn’t enable laptop-mode can also be affected because your harddrive’s firmware or your BIOS might also tell your harddrive to do aggressive power management.

IMHO this bug should get critical status because it’s killing people’s harddrives.

I think we can dissect the bug into the following parts :

• harddrive firmware should use sane defaults for power management (contact your harddrive manufacturer if you don’t use laptop-mode and suffer from this problem)
• the BIOS shouldn’t set the amount of power management of your harddrive (contact your BIOS manufacturer if your harddrive manufacturer isn’t the one to blame)
• harddrives shouldn’t die within one year even if you have enabled aggressive power management settings
• aggressive power management settings (if set by your harddrive’s firmware or your BIOS) should be detected and handled
• laptop-mode should be less aggressive about power management in the meantime you shouldn’t enable it
• if the hdparm service is enabled then hdparm should load the settings from /etc/hdparm.conf after resuming frome suspend-to-ram and hibernate-to-disk
• the top causes for hard drive wake up/spin up should be found
• the top causes for hard drive unparking should be found
• maybe (laptop) harddrives should be mounted with noatime by default
• smartmontools should be installed on default. smartd should run on default with sane settings hooking into a notifier to notify users
  • if the Load_Cycle_Count is increased with more than 90 cycles within 24 hours
  • if smartctl thinks your harddrive assess your harddrive as not healthy
  • if more than X errors where found during the last self-test

Regarding smartd hooking into a notifier I found the following wiki pages with similar ideas :

• SMARTMonitoring
• DiskMonitoring

To view your Load_Cycle_Count :

$sudo aptitude install smartmontools

$sudo smartctl -a /dev/sda | more

Please read this :

• Ubuntu is NOT causing aggressive power management

If you think you might be suffering from this problem here’s an ugly fix :

• the ugly fix

This is what Matthew Garret says about this bug :

Linux-hero wrote about how Ubuntu kills your hard drive. The situation is somewhat less clear than you might think from the article, but the basic takeaway message is that Ubuntu doesn’t touch your hard drive power management settings by default. In almost all cases, it’s more likely to be your BIOS or the firmware on your hard drive.

The script that’s executed when you plug or unplug your laptop is /etc/acpi/power.sh. The relevant sections are:

function laptop_mode_enable {
...
    $HDPARM -S $SPINDOWN_TIME /dev/$drive 2>/dev/null
    $HDPARM -B 1 /dev/$drive 2>/dev/null
}

That is, when the laptop_mode_enable function is called, we set the drive power parameters. Now, by default laptop_mode_enable isn’t called:

if [ x$ENABLE_LAPTOP_MODE = xtrue ]; then
    (sleep 5 && laptop_mode_enable)&
fi

because ENABLE_LAPTOP_MODE is false in the default install (check /etc/default/acpi-support). This means that, by default, we do not alter the hard drive power settings. In other words, the APM settings that your drive is using in Ubuntu are the ones that your BIOS programmed into it when the computer started. This is supported by the fact that people see this issue after resuming from suspend. We don’t touch the hard drive settings at that point, so the only way it can occur is if your BIOS or drive default to this behaviour.

If you enable laptop mode, then we will enable aggressive power management on the drive and that may lead to some reduction in hard drive lifespan. That’s a fairly inevitable consequence of laptop mode, since it only makes sense if the laptop enages in aggressive power management. But, as I said, that’s not the default behaviour of Ubuntu.

There’s certainly an argument that we should work around BIOSes, but in general our assumption has been that your hardware manufacturer has a better idea what your computer is capable of than we do. If a laptop manufacturer configures your drive to save power at the cost of life expectancy, then that’s probably something you should ask your laptop manufacturer about.