Continuing HDD spin ups and downs without laptop-mode.

[Markus Kienast]

I am experiencing weird behavior of my Laptop's HDD, when on Battery. The HDD keeps on spinning up and down in a 10-15 second interval, maybe even less. This happens, when laptop-mode is turned off in /etc/defaults/acpi-support (last line).

This causes my apps to freeze for seconds on spin-up, which is very very annoying. So I am typing an email and don't see the text coming for 5 seconds, then all of it is coming at the same time.

My Laptop is switched to "Powersave" by KDE when unplugged from AC. I have a Sony Vaio VGN-S560P.

It might be, that this also causes my Network Connections being dropped when using Skype.

[Markus Kienast (elias1884)]

What I understand the least is, why does the HDD need to be accessed all the time, when I have 1.5 GB of Ram and nothing special running. Beside Kubuntu-desktop only apache2 and mysql-server are running, but there are no requests to it!

Powersave modes suck in Linux. I suspect one reason for that is that every little app wants to write its configuration to the HDD at all times (NetworkManager) instead of doing that on exit. Who knows what's happening, I am only wild guessing here.

[Matthew Garrett (mjg59)]

ext3 will update the atime of any files that are read, even if they're cached. laptop-mode remounts your filesystems with noatime when on battery, which avoids this.

[Paul Sladen (sladen)]

I can confirm the 'blocking while spin-up' behaviour. However since the application is doing the blocking I don't know there's much that can be done about it if an application is not written with asynchronose I/O in mind.

[Markus Kienast (elias1884)]

On Thursday 20 April 2006 10:49, Paul Sladen wrote:
> I can confirm the 'blocking while spin-up' behaviour. However since the
> application is doing the blocking I don't know there's much that can be
> done about it if an application is not written with asynchronose I/O in
> mind.

How can I find out which application is to blame?

[Kari Aliranta (kpaliran)]

>How can I find out which application is to blame?

Probably the best application for this would be 'atop' from universe, but to monitor disk activity, it requires the kernel patch 'cnt' to be installed - see man pages of atop. At least my Edgy kernel (2.6.17-10 generic) doesn't have that patch by default. Sounds useful, thought.

Anyway, if someone manages to install the patch by him/herself, the command for monitoring disk activity would be 'atop -d'.

[Steve Langasek (vorlon)]

In later versions of Ubuntu, filesystems are mounted using the 'relatime' option by default, so I believe this issue could be considered resolved.