# Hard drive power management in laptops

## gsra99

Has anyone seen this thread in the Ubuntu forums about hard drive power management:

http://ubuntuforums.org/showthread.php?t=805570

Is this a real problem? I noticed that my load cycle count on my brand new hard disk after using Gentoo for 3 months is ~80,000. Which is far to high according to the article. Does anyone know if this will reduce the lifetime of the hard drive? Apparently all laptop hard drives have a minimum load cycle count of 600,000. Generally in all linux os tend to use very aggressive power management settings for hard drives which causes the hard disk head to park every ~1 min, and this causes the load cycle count to increase rapidly. Any information would to useful. I haven't seen this problem mentioned in the forums.

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## d2_racing

I will check my laptop tonight.

But for the rest, I would like to know the answer too  :Smile: 

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## IvanMajhen

My Hitachi HDD, 1.5 years old:

```
Load_Cycle_Count        0x0012   068   068   000    Old_age   Always       -       323472
```

They should work with minimum 600k Load_Cycle_Count.

But why do they count this the same as when drive spins down...   :Confused: 

I have this clicking in XP too.

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## gsra99

I think the load cycle count is when the hard drive 'parks' its head and not when it actually spins down the spindle. They are 2 different things, which are required for power saving on the hard drive. If this is wrong then please let me know.

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## Link31

It happens for me in Gentoo and Windows (actually, it happens also in Grub, so it may be BIOS-related).

I don't think it is very good for the hard drive lifetime... Fortunately, you can fix it, at least from Linux.

Just add this line to /etc/conf.d/hdparm (emerge it if needed):

```
sda_args="-B192"
```

(You could also try other values. Some people use -B255, but I hear some strange noise with this setting)

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## gsra99

I'm currently using -B254 -S242 -M128 with hdparm, and I have reduced my load cycle count drastically, but I have to keep an eye on the HD temperature.

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## d2_racing

```

gentootux ~ # smartctl -H /dev/sda

smartctl version 5.37 [i686-pc-linux-gnu] Copyright (C) 2002-6 Bruce Allen

Home page is http://smartmontools.sourceforge.net/

=== START OF READ SMART DATA SECTION ===

SMART overall-health self-assessment test result: PASSED

gentootux ~ # smartctl -a /dev/sda | grep Load_Cycle_Count

193 Load_Cycle_Count        0x0032   001   001   000    Old_age   Always       -       204698

gentootux ~ #

```

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## IvanMajhen

So, this head parking is dangerous like when disk spins up/down?

It is better then to run some app that reads/writes to disk (like ktorrent, my count then doesn't go up) then when disk is idle?   :Laughing: 

Deactivating this could also leads to more fragile disk when using it on your lap, or against shocks. 

Is there any way to read max Load_Cycle_Count number from disk firmware?

I hope they don't have any evil program in firmware to disable drive when critical count is reached, and disk could still be ok.

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## gsra99

I think the hard disk manufactures only guarantee a minimum load cycle count which is generally 600k for most hd. Therefore, once you reach this then the life span of your hd is in the hands of the gods as they say. I saw several posts on the ubuntu forums where people have said that there hd are beyond the 600k mark. I think someone even posted that there hd was on 1.2m. That is why I wanted to know  how serious an issue this was. Also if you are running a read/write program constantly it does reduce the load cycle count, but to get a drastic reduction you need to use hdparm at boot. I think they recommend a -B200 -S252 for hdparm for a conservative power management setting.

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## d2_racing

 *gsra99 wrote:*   

> I think they recommend a -B200 -S252 for hdparm for a conservative power management setting.

 

And what about someone like me who has a SATA hdd ? Hdparm is not use at all with my disk.

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## Link31

 *HDPARM(8) wrote:*   

> hdparm - get/set SATA/ATA device parameters

 

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## Minthos

Just got a new laptop and its HDD is already at

```
193 Load_Cycle_Count        0x0032   100   100   000    Old_age   Always       -       1307
```

after oly

```
9 Power_On_Hours          0x0032   100   100   000    Old_age   Always       -       80
```

and I can confirm the frequent clicking when idle.

I read about this problem previously and checked my computers for high load cycle count and none of them had the problem. I had assumed HDD manifacturers had switched to more sane default values by now, evidently they have not.

I'm also surprised there is no better fix than hdparm -B 254 written up somewhere. Shouldn't be such a problem to increase the delay before head parking to 5 minutes or so, right? I set my hdparm -B to 240. Don't know how long that is but I hope it's more reasonable than 128 and 254.

There is, however, a package that should avoid this problem; laptop-mode-tools.

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## mrazvan

This seems to bring about neverending discussions as more and more people (like myself) discover the issue and start asking questions, but the hdd manufacturers don't say a word.

I am using laptop_mode_tools under gentoo with little success. The problem is the HDD tries to park its heads too quick. This is a feature of notebook hdds, and on my model (a wd2500bevs) it is labeled (taken from hdparm -I)

```
IDLE IMMEDIATE with UNLOAD
```

which pretty much says it all. No setting apart from B254 (completely disable power management) has any effect on head parking time on my model.

I guess there's really no solution to this other than leaving it as it is.

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