[Bug 59695] Re: High frequency of load/unload cycles on some hard disks may shorten lifetime

Isaac Dupree isaacdupree at charter.net
Sat Dec 20 23:26:41 UTC 2008

Intrepid x86_64 MacBook2,1. (a page related to this hardware:
https://help.ubuntu.com/community/MacBook2-1/Hardy )

bad: Wait 10 minutes (working or not, but system running), and
Load_Cycle_Count increases by 5 to 10.  That's 30-60 LCC an hour, which
is too much.

`hdparm -B 254 /dev/sda` works as long as it lasts, which is until
suspend or reboot.  It seems to prevent Load_Cycle_Count increasing
(except by 1 when suspending to ram or rebooting of course).  My
particular hard-drive specs seem to say that hdparm value will make it
wait 15 minutes before parking the head, so it's possible it would park
after 15 minutes of actual disk inactivity, which would be a good thing
(I wasn't patient enough to check).

Enabling laptop-mode (in /etc/default/acpi-support -- I know it worked
because then, on battery, /proc/sys/vm/laptop_mode would contain 2
rather than 0) didn't solve Load_Cycle_Count increasing, neither when on
battery nor when on AC, and even though /etc/laptop-mode/laptop-
mode.conf settings are mostly good in their default e.g.
possible that both AC and battery are slipping through the cracks in
various ways (maybe battery, uses HD_POWERMGMT=1, and AC, not on LM and
doesn't save disk-writes over time).  (I also noticed that, while writes
can be delayed given enough RAM, reading data from the disk that's not
already cached -- e.g. starting up a new application -- cannot be, so
we're just relying on that not being needed most of the time a
computer's running in laptop-mode.)

I put this into /etc/pm/sleep.d/99-save-hd.sh (with chmod +x) (note bug #244839) :
hdparm -B 254 /dev/sda
It runs, once on each suspend and once on each resume, which works for me (Load_Cycle_Count measured not increasing).  I'm not sure if that script, or indeed anything, runs on system start, though -- but I personally mostly suspend/resume and rarely shut down, so this works good enough for me.

High frequency of load/unload cycles on some hard disks may shorten lifetime
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