laptop harddrive Load_Cycle_Count issue
Don't apply any unofficial ugly fixes unless you understand what you are doing and you understand how to revert. Only apply this fix if you are heavily affected. After applying this fix keep an eye on your Load_Cycle_Count and on your harddrive temperature and make sure it remains below the maximum temperature specification of your harddrive. Also don't forget that having your harddisk head park protects your harddrive if you experience any bumps (which is especially nice if you are on the road and therefor probably working on battery). Everything you do is on your own risk.
Please give me feedback so I can improve this post.
Not everyone is affected but here's a little bit of background.
A lot of laptop drives are affected. Almost no desktop drives are affected except :
* possibly some "very green" drives which use very aggressive power management
* possibly some external drives which use laptop drives.
If your harddrive spins down and spins up again your Load_Cycle_Count increases by one. If your harddrive head parks and unparks again your Load_Cycle_Count increases by one. This is done to save power. Laptop harddrives can handle a limited number of Load_Cycles. Most of harddrives can handle at least 600.000 Load_Cycles but you should look it up for your specific model.
Laptop harddrives use more aggressive power management than desktop harddrives. Some laptop harddrives are using very aggressive power management (set by the laptop harddrive firmware or possibly by some laptop BIOS'es). Aggressive power management will cause your laptop's harddrive head to park quickly. Disk activity will unpark it again.
No disk activity at all will keep it parked. Constant disk activity won't park your harddrive head but this also causes wear and tear (MS Windows might be doing this).
Regular disk activity with periods of no disk activity such as caused by ext3 journalling (which is safer for your data) or such as caused by firefox will park and unpark your harddrive head often. This combination of aggressive power management and regular disk activity is causing too rapidly increasing Load_Cycle_Counts for some people.
Look up how many Load_Cycle_Counts your harddrive can handle (most harddrives can handle 600.000 Load_Cycles but be sure to look it up). Calculate the average difference in Load_Cycle_Count per day. Now calculate what your Load_Cycle_Count will be in three years of harddrive use to determine whether you need to apply the ugly fix. This is explained inside the unofficial ugly fix.
So the causes for the problem are as follows :
* a lot of laptop harddrive firmwares set too aggressive power management settings
* this is probably not a problem for windows because there is probably almost constant disk activity (almost no head parks) so probably laptop harddrive manufacturers don't take this problem seriously
* the average linux laptop doesn't access the disk as often as windows but accesses it too often for a nice and long head park.
The result for some laptop harddrives :
* increasing the Load_Cycle_Count beyond the specifications and therefor risking an early dead.
What we can do now :
* watch our Load_Cycle_Count and harddisk temperature
* we can report unnecessary disk activity bugs which will make our harddrive heads park longer
* for those of us who are heavily affected : the ugly fix is to disable harddrive power management while on AC (no protection from bumps,increased heat) and enable harddrive power management while on battery (increased battery life,protection from bumps, less heat, fast rising Load_Cycle_Count)
The future :
* when linux becomes bigger and bigger on the laptop harddrive manufacturers will take this problem seriously
* flash storage is the future for laptop harddisks and doesn't have this problem (no moving parts)
Unofficial Ugly Load_Cycle_Count Fix for Gutsy
Unofficial Ugly Load_Cycle_Count Fix for Hardy
Idea #288: Fix Hard Drive Load Cycle Problem in Laptops
If you think Load_Cycle_Count didn't rise that quickly before :
* See whether your swap is used (if there's a lot of swapping going on you might want to buy more ram): $ free -m
* Try disabling tracker (system->preferences->search and indexing)
More information :
People should also consider reading the bug. It contains a lot of noise but some posts are very informative such as those by Bart Samwel who maintains laptop-mode-tools and acpi-support in Debian.
https://bugs.launchpad.net/ubuntu/+s...ort/+bug/17216 (same story here. this was the bug while 59695 was slashdotted)
How to help finding disk activity bugs with blktrace (you can also use lm-profiler in addition) :
Possible disk activity bugs :
* the commit interval for the ext3 filesystem should be higher than 5 seconds for laptop users by default (at least while on battery)
* ext3 partitions should be mounted with noatime or relatime
* acpid : Log output far too verbose
* liferea might cause unnecessary disk activity
* thunderbird might cause unnecessary disk activity
* tracker : the index delay should be set to a higher value for laptop users
* firefox might cause unnecessary disk activity when going to a new website
* hddtemp might cause unnecessary disk activity
* tracker and cronjobs (updatedb, update-notifer,...) fight for the hard disk
* Don't install slocate by default on Desktops
* Firefox 3 keeps forcing disk to spin up when browsing because its sqlite storage calls fsync() for every recorded entry
* liferea is slow on updating feeds if you have lots of feeds. multiple threads are needed for updating feeds.
Other related bugs :
laptop-mode-tools uses hparm -B 255 instead of 254 please sync laptop-mode-tools from Debian to fix this
hdparm's feedback about -B values is misleading
using laptop-mode causes system hangs for some people
laptop-mode should default to *always* use relatime for ext3 partitions while keeping the CONTROL_NOATIME option
scripts in /etc/pm/power.d should be called after resuming/ thawing
Please give me feedback so I can improve this post.
Don't apply any unofficial ugly fixes unless you understand what you are doing and you understand how to revert. Only apply this fix if you are heavily affected. After applying this fix keep an eye on your Load_Cycle_Count and on your harddrive temperature and make sure it remains below the maximum temperature specification of your harddrive. Also don't forget that having your harddisk head park protects your harddrive if you experience any bumps (which is especially nice if you are on the road and therefor probably working on battery).Everything you do is on your own risk.
Last edited by ubuntu_demon; May 28th, 2008 at 01:18 PM.