[arch-general] [arch-dev-public] Load_Cycle_Count and storage-fixup

[Stefan Erik Wilkens]

2009/10/29 Aaron Griffin <aaronmgriffin at gmail.com>:
> On Thu, Oct 29, 2009 at 9:31 AM, Xavier <shiningxc at gmail.com> wrote:
>> On Thu, Oct 29, 2009 at 2:08 PM, Michael Towers <larch42 at googlemail.com> wrote:
>>> When I got a new laptop I investigated this problem a little and found
>>> that with hdparm -B 254/255 the temperature went up quite
>>> significantly. This may be a freak and I would love to know whether
>>> there really is something behind it, but when I used -B 200 the
>>> temperature increase was clearly smaller, but the load cycle count did
>>> not increase!!! Is this actually at all possible? Does the -B option
>>> do something other than only affecting head loading? Does anybody
>>> know?
>>>
>>> In looking through the storage-fixup package data I see that always -B
>>> 254 or -B 255 is set, so obviously there is no sign of other, possibly
>>> more optimal values there.
>>>
>>
>> That sounds like an interesting concern, you might want to ask
>> upstream (= storage-fixup maintainers) about it :)
>
> Anyone happen to know how often the storage-fixup rules are updated?
> My Eee drive isn't listed (mine does NOT have an SSD) so I'm not sure
> what the hdparm params should be.
>

>From what I have read on the topic: There is no static answer to "what
it should be". The ammount of times / time unit that a drive should
cycle is dependant on temperature and actual drive use. If it's
sitting still (the laptop it motionless) in a cool area with nothing
at all to do, the drive does not have to cycle.

However, if the laptop is in motion (train, car) and the system is
hot, cycling the drive can reduce heat output and prevent damage to
the drive due to sudden movement. This is why simply setting things to
-B 255 or 254 (which disables the feature completely) is not something
that should be done without at least informing the user.

Through experimentation, I suppose you can find a few values to work
with. From the quick glance I took at storage-fixup, it seems to
disable the feature completely. Does anybody know if it's more
advanced than this or is this the full scope of this script?

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