Arch Linux

The_Air_Penguin

Member

Registered: 2008-12-04

Posts: 12

Hard disk spinning up too often

I read about this laptop mode and it's supposed to keep the disk from spinning up for a long time. I've set it to 15 minutes in /etc/laptop-mode/laptop-mode.conf, but it will only keep the disk down for about a minute or even less. This really scares me because I heard that spinning up and down too often can be harmful to a hard drive.

So I did the debugging to find out what's writing to disk all the time. I used:

su -
/etc/rc.d/syslog-ng stop
echo 1 > /proc/sys/vm/block_dump
dmesg

And then I ran 'dmesg' after each time the disk spins up, just like I found on the laptop mode faq. Sometimes there are spinups because of programs like firefox and I understand that this is something that probably can't be influenced.

However, what bugs me is that 'pdflush' is what's causing most of those spin ups. I thought that it was supposed to write the dirtied files only once every 15 minutes. So what could be causing it to do it so often?

Wittfella

Member

From: Australia

Registered: 2008-05-27

Posts: 462

Re: Hard disk spinning up too often

I just started playing with laptop-mode-tools aswell, and it works ok.  After enabling the hard disk goes silent for ages.

Maybe check the dirty_writeback and see if its set to a large number. Mine is:

cat /proc/sys/vm/dirty_writeback_centisecs
359976

Default is 499 I think.

The_Air_Penguin

Member

Registered: 2008-12-04

Posts: 12

Re: Hard disk spinning up too often

It's 89994 on laptop mode.